user11541: In Mudita meditation or Joy Meditation I am supposed to experience Joy for all beings. But I don't know which aspect of living beings is worth celebrating. 
My question is : How should I express Mudita or Joy for all beings?
EDIT: To support my mental dilemma I quote Maiterya.

Just as there can be no pleasant fragrance in a cesspit There is no
  joy among the five classes of beings.
– Maitreya
Uttaratantra Shastra, IV, 50


user254: I've seen it used in three or four contexts:

It's sometimes said, in a context in which you might expect to hear Sadhu! Sadhu! Sadhu!
Given that understanding Dhamma is the highest good, you might appreciate someone's virtue or good fortune, when they show evidence of that or share that.
It's described as an antidote for envy or jealousy -- i.e. as an alternative to feeling envious of someone's success -- for example here:

If this potential for unselfish joy is widely and methodically encouraged and developed, starting with the Buddhist child (or, for that matter, with any child) and continued with adults (individuals and Buddhist groups, including the Sangha), the seed of mudita can grow into a strong plant which will blossom forth and find fruition in many other virtues, as a kind of beneficial "chain reaction": magnanimity, tolerance, generosity (of both heart and purse), friendliness, and compassion. When unselfish joy grows, many noxious weeds in the human heart will die a natural death (or will, at least, shrink): jealousy and envy, ill will in various degrees and manifestations, cold-heartedness, miserliness (also in one's concern for others), and so forth. Unselfish joy can, indeed, act as a powerful agent in releasing dormant forces of the Good in the human heart.
We know very well how envy and jealousy (the chief opponents of unselfish joy) can poison a man's character as well as the social relationships on many levels of his life. They can paralyze the productivity of society, on governmental, professional, industrial, and commercial levels. Should not, therefore, all effort be made to cultivate their antidote, that is mudita?

The same quote (above) continues, that it's also an antidote to "a condescending and patronizing attitude":

Mudita will also vitalize and ennoble charitable and social work. While compassion (karuna [karu.naa]) is, or should be, the inspiration for it, unselfish joy should be its boon companion. Mudita will prevent compassionate action from being marred by a condescending and patronizing attitude which often repels or hurts the recipient. Also, when active compassion and unselfish joy go together, it will be less likely that works of service turn into dead routine performed indifferently. Indifference, listlessness, boredom (all nuances of the Pali term arati) are said to be the 'distant enemies' of mudita. They can be vanquished by an alliance of compassion and unselfish joy.

Perhaps it may be used in a more general situation:

If someone really has no problems, that's great, they are Enlightened! The historical Buddha (According to Stephen Batchelor's retelling) said as much on his death bed, when he asked if anyone had any questions left, no one did, so he said, well you all must be enlightened then. People need Buddhism when their current raft has sunk. If there is food on the table, a comfortable place to sleep, and they have no complaints about their daily routine, then our jobs as Buddhists is to rejoice in their success (mudita).

So as well as being an antidote to jealousy, perhaps it's also an antidote to excess of compassion.
I read (unfortunately I haven't been able to find it again) an article explaining, about the the four brahmaviharas, that sometimes one is an antidote to an excess of another -- for example if you feel too much of one, then you might want some equanimity. Perhaps similarly if you feel too much 'pity', then you might want some mudita, to consider what the person does have in the way good fortune or attainment.


user14833: To express Mudita or Joy for all beings, means cultivating Mudita Meditation ?
From most common brahmavihara (Maithree) to most difficult an un-attempted brahmavihara (Mudita) of cultivation of the four (04) brahmaviharas.
If I ask myself the question : How can I cultivate Mudita ?
Simple answer is to lessen (mitigate) or to reduce the intensity of feeling envy or jealousy over others' actions, words and achievements etc. 
Before being joyful in one's happiness (which is very difficult unless I am abnormally a thorough practitioner of cultivating  brahmaviharas, and close to a quality of person attaining near self-actualization (or a Bodhisathva)) I should try to be devoid of envy of other people's happiness.
If tiny bit of jealousy or envy is left in our mind we cannot begin mudita meditation.The mudita meditation begins at the endpoint of non-envy and non-joy in others' happiness or well-being. That is when I am unmoved by one's own happiness or sorrow for that matter. 
From that point onward, I can cultivate mudita meditation with ease. Because I am devoid of envy and I am honestly longing for mudita. So henceforth my mind would be upstream MUDITA and I have no hindering thoughts over being joyful in others' joy.
So I should say myself, that now I am on the threshold of practising Mudita Meditation meaningfully and diligently and effectively.
So foremost prerequisite of Mudita meditation is to nullify whatever envy, jealousy over others' behaviour and achievements. 
Mudita meditation begins from the point of no-envy.

user14827: First of all one has to associate with people who practice mudita in daily live and are joyful in sharing their merits. This is something one would not easy find in "outer lands" (i.e. outside a monastery).
Second, to not practice it wrong, one has to know and understand what is a good and a bad deed, a conductive attainment or a hindrance -- otherwise you could possibly think that looking at popstars, and people jumping while watching them, is a place for proper mudita. That's a place for karuna...
Mudita means to remember and honor good attainments of other beings -- where there are no beings who had not done good, or accumulate good, in the present or past. If dwelling under people with wrong view, if even such as appreciation is usual, one would just increase one's defilements.
There is a list of reasons and people who are incapable of mudita, mostly caused by stinginess (macchariya), and aside of mind connected with unskillfullness, traders are counted to be incapable for appreciation.
Some may think of reflecting on a "Buddhanature", but actually mudita is the right way to do that. Understanding "Buddhanature", seeing the reason what to appreciate in all beings so to develop mudita in the context of Buddha's good teachings is worthy to understand; and of course, people from a Bodhisatta background have a better training in the basics of mudita (yet often with wrong view, such as inherent goodness).
For more and detail explaining see:  Sharing merits - Freude teilen (pattanumodana & pattidana) [Forum Guide]
And since maccharia (stinginess) or amudita makes it impossible to reach even Jhana, not to speak about path or fruits, this words might be useful in addition: What's the reason that stinginess (macchariya) would disappear?
My person missed that the question includes already the wise detail question, Sadhu!
But I don't know which aspect of living beings is worth celebrating.
What ever of the real treasures, causes for such or effects by receiving the results can be seen and traced in beings.
And what are the real treasures?

"There are these seven treasures. Which seven? The treasure of conviction, the treasure of virtue, the treasure of conscience, the treasure of concern, the treasure of listening, the treasure of generosity, the treasure of discernment. ...Dhana Sutta: Treasure

See further topic to get into detail if wished, since discussion, exchange for clarification, is not welcome here: [Q&A] How should I express Mudita or Joy for all beings?
[Since a gift with mudita is not an approval of inproper not to happiness leading attainments: this is not given for trade, exchanges or other stock increasing bond to world.]

user471: Here's an excerpt from the Visuddhimagga (The Path of Purification) authored by Buddhaghosa in the 5th century. It's entitled "The Meditative Development of Unselfish Joy":

One who begins the development of unselfish joy should not start with
  dearly beloved person, a neutral person or hostile person. For it is
  not the mere fact that a person is dearly beloved, which makes him an
  immediate cause of developing unselfish joy, and still less so neutral
  or hostile person. Persons of the opposite sex and those who are dead
  are not suitable subjects for this meditation.
A very close friend, however, can be a suitable subject. One who is
  called in the commentaries an affectionate companion; for he is always
  in a joyous mood: he laughs first and speaks afterwards. He should be
  the first to be pervaded with unselfish joy. Or on seeing or hearing
  about a dear person being happy, cheerful, and joyous, unselfish joy
  can be aroused thus: "This being, verily, is happy! How good, how
  excellent!" For this is what is referred to in the Vibhanga: "And how
  does a bhikkhu dwell pervading one direction with his heart imbued
  with unselfish joy? Just as he would be joyful on seeing a dear and
  beloved person, so he pervades all being with unselfish joy" (Vibhanga
  274).
But if his affectionate friend or the dear person was happy in the
  past but is now unlucky and unfortunate, then unselfish joy can still
  be aroused by remembering his past happiness; or by anticipating that
  he will be happy and successful again in the future.
Having thus aroused unselfish joy with respect to a dear person, the
  meditator can then direct it towards a neutral one, and after that
  towards a hostile one.
But if resentment towards the hostile one arises in him, he should
  make it subside in the same way as described under the exposition of
  loving-kindness.
He should then break down the barriers by means of impartiality
  towards the four, that is, towards these three and himself. And by
  cultivating the sign (or after-image, obtained in concentration),
  developing and repeatedly practicing it, he should increase the
  absorption to triple or (according to the Abhidhamma division)
  quadruple jhana.
Next, the versatility (in this meditation) should be understood in the
  same way as stated under loving-kindness. It consists in:
(a) Unspecified pervasion in these five ways:
      "May all beings... all breathing things... all creatures... all persons... all those who have a personality be free from enmity,
  affliction, and anxiety, and live happily!"
(b) Specified pervasion in
  these seven ways:
      "May all women... all men... all Noble Ones... all not Noble Ones... all deities... all human beings... all in states of misery (in
  lower worlds) be free from enmity, etc."
(c) Directional pervasion in
  these ten ways:
      "May all beings (all breathing things, etc.; all women, etc.) in the eastern direction... in the western direction... northern...
  southern direction... in the intermediate eastern, western, northern,
  and southern direction... in the downward direction... in the upward
  direction be free from enmity, etc."
This versatility is successful only in one whose mind has reached
  absorption (jhana).
When this meditator develops the mind-deliverance of unselfish joy
  through any of these kinds of absorption he obtains these eleven
  advantages: he sleeps in comfort, wakes in comfort, and dreams no evil
  dreams, he is dear to human beings, dear to non-human beings, deities
  guard him, fire and poison and weapons do not affect him, his mind is
  easily concentrated, the expression of his face is serene, he dies
  unconfused, if he penetrates no higher he will be reborn in the Brahma
  World (A v 342).


user43: The aspect that I celebrate: that despite all the difficulties, suffering, dirt, cynicism, pain etc. people still find strength to be positive, to love, to forgive, and to create beauty. Especially people who have seen difficulties are often the kindest and the most understanding of all. I think this is very beautiful. 

user10100: Anumodanā is expressing joy to wholesome-causes, actions (all living beings), which will give good effects.
Muditā is expressing joy to wholesome's effects, resultants (all living beings), which gave from good causes.
So, you should express your joy to all  wholesome's resultants, but you should not express your joy to all unwholesome-actions.
Ex: a thief rob successfully without arrest. This case, we muditā to the thief's "living without arrest" (resultants), but we don't anumodanā with his thieving (actions). And we don't say/feel "serves you right" to that thief, because we are being muditā, not being jealous (muditā's enemy) him.
Note:
Resultant (effect) = resultant-paṭiccasamuppāda, such as vipākaviññāṇa/nāmarūpa/salāyatana/phassa/vedanā/uppattibhava/jāti/jarā/maraṇa. 
Action (cause) = avijjā/saṅkhāra/taṇhā/upādāna/kammbhava.
By that paṭiccasamuppāda, all thieves' living being are effects of past live wholesome-action, because if not, he should be in apāya.
All as a living being (satta), not paramattha.

11541: <p>In Mudita meditation or Joy Meditation I am supposed to experience Joy for all beings. But I don't know which aspect of living beings is worth celebrating. </p>

<p>My question is : How should I express Mudita or Joy for all beings?</p>

<p>EDIT: To support my mental dilemma I quote Maiterya.</p>

<blockquote>
  <p>Just as there can be no pleasant fragrance in a cesspit There is no
  joy among the five classes of beings.</p>
  
  <p>– Maitreya</p>
  
  <p>Uttaratantra Shastra, IV, 50</p>
</blockquote>
 254: <p>I've seen it used in three or four contexts:</p>

<ol>
<li><p>It's sometimes said, in a context in which you might expect to hear <a href="https://buddhism.stackexchange.com/q/9033/254"><em>Sadhu! Sadhu! Sadhu!</em></a></p>

<p>Given that understanding Dhamma is the highest good, you might appreciate someone's virtue or good fortune, when they show evidence of that or share that.</p></li>
<li><p>It's described as an antidote for envy or jealousy -- i.e. as an alternative to feeling envious of someone's success -- for example <a href="https://www.accesstoinsight.org/lib/authors/various/wheel170.html" rel="nofollow noreferrer">here</a>:</p>

<blockquote>
  <p>If this potential for unselfish joy is widely and methodically encouraged and developed, starting with the Buddhist child (or, for that matter, with any child) and continued with adults (individuals and Buddhist groups, including the Sangha), the seed of mudita can grow into a strong plant which will blossom forth and find fruition in many other virtues, as a kind of beneficial "chain reaction": magnanimity, tolerance, generosity (of both heart and purse), friendliness, and compassion. When unselfish joy grows, many noxious weeds in the human heart will die a natural death (or will, at least, shrink): jealousy and envy, ill will in various degrees and manifestations, cold-heartedness, miserliness (also in one's concern for others), and so forth. Unselfish joy can, indeed, act as a powerful agent in releasing dormant forces of the Good in the human heart.</p>
  
  <p>We know very well how envy and jealousy (the chief opponents of unselfish joy) can poison a man's character as well as the social relationships on many levels of his life. They can paralyze the productivity of society, on governmental, professional, industrial, and commercial levels. Should not, therefore, all effort be made to cultivate their antidote, that is mudita?</p>
</blockquote></li>
<li><p>The same quote (above) continues, that it's also an antidote to "a condescending and patronizing attitude":</p>

<blockquote>
  <p>Mudita will also vitalize and ennoble charitable and social work. While compassion (karuna [karu.naa]) is, or should be, the inspiration for it, unselfish joy should be its boon companion. Mudita will prevent compassionate action from being marred by a condescending and patronizing attitude which often repels or hurts the recipient. Also, when active compassion and unselfish joy go together, it will be less likely that works of service turn into dead routine performed indifferently. Indifference, listlessness, boredom (all nuances of the Pali term arati) are said to be the 'distant enemies' of mudita. They can be vanquished by an alliance of compassion and unselfish joy.</p>
</blockquote></li>
<li><p>Perhaps it may be used in <a href="https://buddhism.stackexchange.com/a/7275/254">a more general situation</a>:</p>

<blockquote>
  <p>If someone really has no problems, that's great, they are Enlightened! The historical Buddha (According to Stephen Batchelor's retelling) said as much on his death bed, when he asked if anyone had any questions left, no one did, so he said, well you all must be enlightened then. People need Buddhism when their current raft has sunk. If there is food on the table, a comfortable place to sleep, and they have no complaints about their daily routine, then our jobs as Buddhists is to rejoice in their success (mudita).</p>
</blockquote>

<p>So as well as being an antidote to jealousy, perhaps it's also an antidote to excess of compassion.</p>

<p>I read (unfortunately I haven't been able to find it again) an article explaining, about the the four brahmaviharas, that sometimes one is an antidote to an excess of another -- for example if you feel too much of one, then you might want some equanimity. Perhaps similarly if you feel <a href="https://buddhism.stackexchange.com/q/9997/254">too much 'pity'</a>, then you might want some <em>mudita</em>, to consider what the person does have in the way good fortune or attainment.</p></li>
</ol>
 14833: <p>To express Mudita or Joy for all beings, means cultivating Mudita Meditation ?</p>

<p>From most common brahmavihara (Maithree) to most difficult an un-attempted brahmavihara (Mudita) of cultivation of the four (04) brahmaviharas.</p>

<p>If I ask myself the question : How can I cultivate Mudita ?</p>

<p>Simple answer is to lessen (mitigate) or to reduce the intensity of feeling envy or jealousy over others' actions, words and achievements etc. </p>

<p>Before being joyful in one's happiness (which is very difficult unless I am abnormally a thorough practitioner of cultivating  brahmaviharas, and close to a quality of person attaining near self-actualization (or a Bodhisathva)) I should try to be devoid of envy of other people's happiness.</p>

<p>If tiny bit of jealousy or envy is left in our mind we cannot begin mudita meditation.The mudita meditation begins at the endpoint of non-envy and non-joy in others' happiness or well-being. That is when I am unmoved by one's own happiness or sorrow for that matter. </p>

<p>From that point onward, I can cultivate mudita meditation with ease. Because I am devoid of envy and I am honestly longing for mudita. So henceforth my mind would be upstream MUDITA and I have no hindering thoughts over being joyful in others' joy.</p>

<p>So I should say myself, that now I am on the threshold of practising Mudita Meditation meaningfully and diligently and effectively.</p>

<p>So foremost prerequisite of Mudita meditation is to nullify whatever envy, jealousy over others' behaviour and achievements. </p>

<p>Mudita meditation begins from the point of no-envy.</p>
 14827: <p>First of all one has to associate with people who practice mudita in daily live and are joyful in sharing their merits. This is something one would not easy find in "outer lands" (i.e. outside a monastery).</p>

<p>Second, to not practice it wrong, one has to know and understand what is a good and a bad deed, a conductive attainment or a hindrance -- otherwise you could possibly think that looking at popstars, and people jumping while watching them, is a place for proper mudita. That's a place for karuna...</p>

<p>Mudita means to remember and honor good attainments of other beings -- where there are no beings who had not done good, or accumulate good, in the present or past. If dwelling under people with wrong view, if even such as appreciation is usual, one would just increase one's defilements.</p>

<p>There is a list of reasons and people who are incapable of mudita, mostly caused by stinginess (macchariya), and aside of mind connected with unskillfullness, traders are counted to be incapable for appreciation.</p>

<p>Some may think of reflecting on a "Buddhanature", but actually mudita is the right way to do that. Understanding "Buddhanature", seeing the reason what to appreciate in all beings so to develop mudita in the context of Buddha's good teachings is worthy to understand; and of course, people from a Bodhisatta background have a better training in the basics of mudita (yet often with wrong view, such as inherent goodness).</p>

<p>For more and detail explaining see:  <a href="http://sangham.net/index.php/topic,326.msg13806.html#msg13806" rel="nofollow noreferrer">Sharing merits - Freude teilen (pattanumodana &amp; pattidana) [Forum Guide]</a></p>

<p>And since maccharia (stinginess) or amudita makes it impossible to reach even Jhana, not to speak about path or fruits, this words might be useful in addition: <a href="http://sangham.net/index.php/topic,9093.msg17438.html#msg17438" rel="nofollow noreferrer">What's the reason that stinginess (macchariya) would disappear?</a></p>

<p>My person missed that the question includes already the wise detail question, Sadhu!</p>

<p><strong>But I don't know which aspect of living beings is worth celebrating.</strong></p>

<p>What ever of the real treasures, causes for such or effects by receiving the results can be seen and traced in beings.</p>

<p>And what are the real treasures?</p>

<blockquote>
  <p>"There are these seven treasures. Which seven? The treasure of conviction, the treasure of virtue, the treasure of conscience, the treasure of concern, the treasure of listening, the treasure of generosity, the treasure of discernment. ...<a href="http://zugangzureinsicht.org/html/tipitaka/an/an07/an07.006.than_en.html" rel="nofollow noreferrer">Dhana Sutta: Treasure</a></p>
</blockquote>

<p>See further topic to get into detail if wished, since discussion, exchange for clarification, is not welcome here: <a href="http://sangham.net/index.php/topic,9139.msg17823.html#msg17823" rel="nofollow noreferrer">[Q&amp;A] How should I express Mudita or Joy for all beings?</a></p>

<p><em>[Since a gift with mudita is not an approval of inproper not to happiness leading attainments: this is not given for trade, exchanges or other stock increasing bond to world.]</em></p>
 471: <p>Here's an excerpt from the Visuddhimagga (The Path of Purification) authored by Buddhaghosa in the 5th century. It's entitled "<a href="https://www.accesstoinsight.org/lib/authors/various/wheel170.html#meditative" rel="nofollow noreferrer">The Meditative Development of Unselfish Joy</a>":</p>

<blockquote>
  <p>One who begins the development of unselfish joy should not start with
  dearly beloved person, a neutral person or hostile person. For it is
  not the mere fact that a person is dearly beloved, which makes him an
  immediate cause of developing unselfish joy, and still less so neutral
  or hostile person. Persons of the opposite sex and those who are dead
  are not suitable subjects for this meditation.</p>
  
  <p>A very close friend, however, can be a suitable subject. One who is
  called in the commentaries an affectionate companion; for he is always
  in a joyous mood: he laughs first and speaks afterwards. He should be
  the first to be pervaded with unselfish joy. Or on seeing or hearing
  about a dear person being happy, cheerful, and joyous, unselfish joy
  can be aroused thus: "This being, verily, is happy! How good, how
  excellent!" For this is what is referred to in the Vibhanga: "And how
  does a bhikkhu dwell pervading one direction with his heart imbued
  with unselfish joy? Just as he would be joyful on seeing a dear and
  beloved person, so he pervades all being with unselfish joy" (Vibhanga
  274).</p>
  
  <p>But if his affectionate friend or the dear person was happy in the
  past but is now unlucky and unfortunate, then unselfish joy can still
  be aroused by remembering his past happiness; or by anticipating that
  he will be happy and successful again in the future.</p>
  
  <p>Having thus aroused unselfish joy with respect to a dear person, the
  meditator can then direct it towards a neutral one, and after that
  towards a hostile one.</p>
  
  <p>But if resentment towards the hostile one arises in him, he should
  make it subside in the same way as described under the exposition of
  loving-kindness.</p>
  
  <p>He should then break down the barriers by means of impartiality
  towards the four, that is, towards these three and himself. And by
  cultivating the sign (or after-image, obtained in concentration),
  developing and repeatedly practicing it, he should increase the
  absorption to triple or (according to the Abhidhamma division)
  quadruple jhana.</p>
  
  <p>Next, the versatility (in this meditation) should be understood in the
  same way as stated under loving-kindness. It consists in:</p>
  
  <p>(a) Unspecified pervasion in these five ways:
      "May all beings... all breathing things... all creatures... all persons... all those who have a personality be free from enmity,
  affliction, and anxiety, and live happily!"</p>
  
  <p>(b) Specified pervasion in
  these seven ways:
      "May all women... all men... all Noble Ones... all not Noble Ones... all deities... all human beings... all in states of misery (in
  lower worlds) be free from enmity, etc."</p>
  
  <p>(c) Directional pervasion in
  these ten ways:
      "May all beings (all breathing things, etc.; all women, etc.) in the eastern direction... in the western direction... northern...
  southern direction... in the intermediate eastern, western, northern,
  and southern direction... in the downward direction... in the upward
  direction be free from enmity, etc."</p>
  
  <p>This versatility is successful only in one whose mind has reached
  absorption (jhana).</p>
  
  <p>When this meditator develops the mind-deliverance of unselfish joy
  through any of these kinds of absorption he obtains these eleven
  advantages: he sleeps in comfort, wakes in comfort, and dreams no evil
  dreams, he is dear to human beings, dear to non-human beings, deities
  guard him, fire and poison and weapons do not affect him, his mind is
  easily concentrated, the expression of his face is serene, he dies
  unconfused, if he penetrates no higher he will be reborn in the Brahma
  World (A v 342).</p>
</blockquote>
 43: <p>The aspect that I celebrate: that despite all the difficulties, suffering, dirt, cynicism, pain etc. people still find strength to be positive, to love, to forgive, and to create beauty. Especially people who have seen difficulties are often the kindest and the most understanding of all. I think this is very beautiful. </p>
 10100: <p>Anumodanā is expressing joy to wholesome-causes, actions (all living beings), which will give good effects.</p>

<p>Muditā is expressing joy to wholesome's effects, resultants (all living beings), which gave from good causes.</p>

<p><strong>So, you should express your joy to all  wholesome's resultants, but you should not express your joy to all unwholesome-actions.</strong></p>

<p>Ex: a thief rob successfully without arrest. This case, we <strong>muditā</strong> to the thief's "living without arrest" (resultants), but we don't <strong>anumodanā</strong> with his thieving (actions). And we don't say/feel "serves you right" to that thief, because we are being muditā, not being jealous (<a href="https://en.wikipedia.org/wiki/Mudita" rel="nofollow noreferrer">muditā's enemy</a>) him.</p>

<p><strong>Note:</strong></p>

<p><strong>Resultant (effect)</strong> = resultant-paṭiccasamuppāda, such as vipākaviññāṇa/nāmarūpa/salāyatana/phassa/vedanā/uppattibhava/jāti/jarā/maraṇa. </p>

<p><strong>Action (cause)</strong> = avijjā/saṅkhāra/taṇhā/upādāna/kammbhava.</p>

<p>By that paṭiccasamuppāda, all thieves' living being are effects of past live <strong>wholesome-action</strong>, because if not, he should be in apāya.</p>

<p>All as a living being (satta), not paramattha.</p>
