user-1: Regardless of a meditation's perceived quality, I feel that finishing a meditation provides some sense of accomplishment.
Nowadays, I am experiencing great lack of motivation, and when I set the goal of meditation as '30 minutes', I stop half-way and feel that I failed. 
Knowing how finishing things provides accomplishment, would it make more sense setting shorter times which I can finish? Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general? Or, is such a feeling of success a kind of attachment, and problematic? 
Thank you

user-1: 
Knowing how finishing things provides accomplishment, would it make more sense setting shorter times which I can finish?

That seems like a situation where you would oblige your craving. 

Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general? 

Yes. But momentum in a buddhist sense is likely to occur by letting go of attachment or achieving. It’s the art of no art to paraphrase Bruce Lee. 

Or, is such a feeling of success a kind of attachment, and problematic?

Yes and yes. 

user-1: If you struggle with motivation you can consider formally contemplating, can even start with 3-5 minutes.
Mn95;

"Exertion is most helpful for the final attainment of the truth, Bharadvaja. If one didn't make an exertion, one wouldn't finally attain the truth. Because one makes an exertion, one finally attains the truth. Therefore, exertion is most helpful for the final attainment of the truth."
"But what quality is most helpful for exertion? We ask Master Gotama about the quality most helpful for exertion."
"Contemplating is most helpful for exertion, Bharadvaja. If one didn't contemplate, one wouldn't make an exertion. Because one contemplates, one makes an exertion. Therefore, contemplating is most helpful for exertion."
"But what quality is most helpful for contemplating?..."
"Being willing... If one weren't willing, one wouldn't contemplate..."
"But what quality is most helpful for being willing?..."
"Desire... If desire didn't arise, one wouldn't be willing..."
"But what quality is most helpful for desire?..."
"Coming to an agreement through pondering dhammas... If one didn't come to an agreement through pondering dhammas, desire wouldn't arise..."

I would also beware of this line of thinking; 'I am good/bad because of "X". It affirms and is of the notion of 'I am' which is a verbalization of craving and will make it minds inclination if pondered frequently.

Dvedhavitakka Sutta: Two Sorts of Thinking -
"Whatever a monk keeps pursuing with his thinking & pondering, that becomes the inclination of his awareness.

See the tanha sutta as well for craving ref.

user295: 
OP: would it make more sense setting shorter times which I can finish?

When one does not have Sampajañña, i.e., know there is a sensation and know it is impermanent one is accumulating Sankhara / Karma. 1
In daily activities, a novice generally does not have Sampajañña, therefore accumulates Sankhara.
When one is in proper meditation (not merely sitting on a cushion distracted) one does not accumulate sankhara and also dilutes the effects of past sankhara.
Also during a meditation session, there are times one remains distracted and it might take a while to settle into a serious meditation.
Therefore a meditation session should be sufficiently long to compensate for distraction during meditation and the lack of Sampajañña during daily activities. Short sessions may not give desired results. E.g.

polishing brass takes some time to remove the oxidisation. If you do this for a short time then this will not restore the shine.
to create fire one needs to rub 2 sticks until they catch fire. If you stop rubbing prematurely it does not light up.


OP: Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general? Or, is such a feeling of success a kind of attachment, and problematic?

If one tries to perceive the quality of a meditation session this leads to disappointment or satisfaction. This counters what meditation tries to achieve that is not to be averse or attached.

1

Know the feeling


i. On seeing a form with the eye,

one investigates the form that is the basis for mental joy,
one investigates the form that is the basis of mental pain,
one investigates the form that is the basis of equanimity.

ii. On hearing a sound with the ear,

one investigates the sound that is the basis for mental joy,
one investigates the sound that is the basis of mental pain,
one investigates the sound that the basis of equanimity.

iii. On smelling a smell with the nose,

one investigates the smell that is the basis for mental joy,
one investigates the smell that is the basis of mental pain,
one investigates the smell that is the basis of equanimity.

iv. On tasting a taste with the tongue,

one investigates the taste that is the basis for mental joy,
one investigates the taste that is the basis of mental pain,
one investigates the taste that is the basis of equanimity.

v. On feeling a touch with the body,

one investigates the touch that is the basis for mental joy,
one investigates the touch that is the basis of mental pain,
one investigates the touch that is the basis of equanimity.

vi. On cognizing a mind-object with the mind,

one investigates the mind-object that the basis of mental joy,
one investigates the mind-object that is the basis of mental pain,
one investigates the mind-object that is the basis of equanimity.


Dhātu Vibhaṅga Sutta

Know that the feels are impermanent so do not cling onto them


If he feels a pleasant feeling,

he understands that it is impermanent;
he understands that it is not to be clung to;
he understands that there is no delight in it.

If he feels a painful feeling,

he understands that it is impermanent;
he understands that it is not to be clung to;
he understands that there is no delight in it.

If he feels a neutral feeling,

he understands that it is impermanent;
he understands that it is not to be clung to;
he understands that there is no delight in it.

If he feels a pleasant feeling, he feels it in a detached manner.
If he feels a painful feeling, he feels it in a detached manner.
If he feels a neutral feeling, he feels it in a detached manner.

Dhātu Vibhaṅga Sutta

user16612: Yes, you can develop a momentum in meditation. After consistent and prolonged practice with discipline, meditation get's it's momentum. I know this from mantra meditation. You fill your mind with spiritual impressions. In beginning it won't be easy because your miind is not used to meditation. But over time, as you get used to the practice of meditation, it will be easier and easier to start meditating.

user471: Here are some excellent advice given by Ajaan Fuang in "Awareness Itself":

§ "When the meditation goes well, don't get excited. When it doesn't
  go well, don't get depressed. Simply be observant to see why it's
  good, why it's bad. If you can be observant like this, it won't be
  long before your meditation becomes a skill."
§ A young nurse practiced meditation with Ajaan Fuang several days
  running, and finally asked him one day, "Why wasn't today's session as
  good as yesterday's?"
He answered: "Meditating is like wearing clothes. Today you wear
  white, tomorrow red, yellow, blue, whatever. You have to keep
  changing. You can't wear the same set of clothes all the time. So
  whatever color you're wearing, just be aware of it. Don't get
  depressed or excited about it."
§ A few months later the same nurse was sitting in meditation when a
  sense of peace and clarity in her mind became so intense that she felt
  she would never have a bad mood infiltrate her mind again. But sure
  enough, bad moods eventually came back as before. When she mentioned
  this to Ajaan Fuang, he said, "Looking after the mind is like raising
  a child. There will have to be bad days along with the good. If you
  want only the good, you're in for trouble. So you have to play
  neutral: Don't fall in with the good or the bad."
§ A student came to complain to Ajaan Fuang that she had been
  meditating for years, and still hadn't gotten anything out of it. His
  immediate response: "You don't meditate to 'get' anything. You
  meditate to let go."
§ "Don't make a journal of your meditation experiences. If you do,
  you'll start meditating in order to have this or that thing happen, so
  that you can write it down in your journal. And as a result, you'll
  end up with nothing but the things you've fabricated."
§ "You can't plan the way your practice is going to go. The mind has
  its own steps and stages, and you have to let the practice follow in
  line with them. That's the only way you'll get genuine results.
  Otherwise you'll turn into a half-baked arahant."
§ "When the mind's not quiet — that's when its poor and burdened with
  difficulties. It takes molehills and turns them into mountains. But
  when the mind is quiet, there's no suffering, because there's nothing
  at all. No mountains at all. When there's a lot to the mind, it's
  simply a lot of defilement, making it suffer."

Maybe you can give yourself the flexibility of meditating between 15 to 30 minutes. At the end of it, don't cling to any result/ state, and be observant about why today's session was the way it was. If today's session was not good, it's not because you had failed. It was probably due to some defilement entering the mind. Then that would lead you to identify how the defilement came into the mind. That's more skillful than blaming yourself.

-1: <p>Regardless of a meditation's perceived <em>quality</em>, I feel that finishing a meditation provides some sense of accomplishment.</p>

<p>Nowadays, I am experiencing great lack of motivation, and when I set the goal of meditation as '30 minutes', I stop half-way and feel that I failed. </p>

<p>Knowing how finishing things provides accomplishment, would it make more sense setting <em>shorter</em> times which I can finish? <strong>Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general?</strong> Or, is such a feeling of success a kind of attachment, and problematic? </p>

<p>Thank you</p>
 -1: <blockquote>
  <p>Knowing how finishing things provides accomplishment, would it make more sense setting shorter times which I can finish?</p>
</blockquote>

<p>That seems like a situation where you would oblige your craving. </p>

<blockquote>
  <p>Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general? </p>
</blockquote>

<p>Yes. But momentum in a buddhist sense is likely to occur by letting go of attachment or achieving. It’s the art of no art to paraphrase Bruce Lee. </p>

<blockquote>
  <p>Or, is such a feeling of success a kind of attachment, and problematic?</p>
</blockquote>

<p>Yes and yes. </p>
 -1: <p>If you struggle with motivation you can consider formally contemplating, can even start with 3-5 minutes.</p>
<p>Mn95;</p>
<blockquote>
<p>&quot;Exertion is most helpful for the final attainment of the truth, Bharadvaja. If one didn't make an exertion, one wouldn't finally attain the truth. Because one makes an exertion, one finally attains the truth. Therefore, exertion is most helpful for the final attainment of the truth.&quot;</p>
<p>&quot;But what quality is most helpful for exertion? We ask Master Gotama about the quality most helpful for exertion.&quot;</p>
<p>&quot;Contemplating is most helpful for exertion, Bharadvaja. If one didn't contemplate, one wouldn't make an exertion. Because one contemplates, one makes an exertion. Therefore, contemplating is most helpful for exertion.&quot;</p>
<p>&quot;But what quality is most helpful for contemplating?...&quot;</p>
<p>&quot;Being willing... If one weren't willing, one wouldn't contemplate...&quot;</p>
<p>&quot;But what quality is most helpful for being willing?...&quot;</p>
<p>&quot;Desire... If desire didn't arise, one wouldn't be willing...&quot;</p>
<p>&quot;But what quality is most helpful for desire?...&quot;</p>
<p>&quot;Coming to an agreement through pondering dhammas... If one didn't come to an agreement through pondering dhammas, desire wouldn't arise...&quot;</p>
</blockquote>
<p>I would also beware of this line of thinking; 'I am good/bad because of &quot;X&quot;. It affirms and is of the notion of 'I am' which is a verbalization of craving and will make it minds inclination if pondered frequently.</p>
<blockquote>
<p>Dvedhavitakka Sutta: Two Sorts of Thinking -
&quot;Whatever a monk keeps pursuing with his thinking &amp; pondering, that becomes the inclination of his awareness.</p>
</blockquote>
<p>See the tanha sutta as well for craving ref.</p>
 295: <blockquote>
<p><strong>OP: would it make more sense setting shorter times which I can finish?</strong></p>
</blockquote>
<p>When one does not have <a href="https://en.wikipedia.org/wiki/Sampaja%C3%B1%C3%B1a" rel="nofollow noreferrer">Sampajañña</a>, i.e., know there is a sensation and know it is impermanent one is accumulating Sankhara / Karma. <sup>1</sup></p>
<p>In daily activities, a novice generally does not have <a href="https://en.wikipedia.org/wiki/Sampaja%C3%B1%C3%B1a" rel="nofollow noreferrer">Sampajañña</a>, therefore accumulates Sankhara.</p>
<p>When one is in proper meditation (not merely sitting on a cushion distracted) one does not accumulate sankhara and also dilutes the effects of past sankhara.</p>
<p>Also during a meditation session, there are times one remains distracted and it might take a while to settle into a serious meditation.</p>
<p>Therefore a meditation session should be sufficiently long to compensate for distraction during meditation and the lack of <a href="https://en.wikipedia.org/wiki/Sampaja%C3%B1%C3%B1a" rel="nofollow noreferrer">Sampajañña</a> during daily activities. Short sessions may not give desired results. E.g.</p>
<ul>
<li>polishing brass takes some time to remove the oxidisation. If you do this for a short time then this will not restore the shine.</li>
<li>to create fire one needs to rub 2 sticks until they catch fire. If you stop rubbing prematurely it does not light up.</li>
</ul>
<blockquote>
<p><strong>OP: Is there such a thing as the momentum of accomplishment in meditation or even in virtuous activity in general? Or, is such a feeling of success a kind of attachment, and problematic?</strong></p>
</blockquote>
<p>If one tries to perceive the quality of a meditation session this leads to disappointment or satisfaction. This counters what meditation tries to achieve that is not to be averse or attached.</p>
<hr />
<p><sup>1</sup></p>
<ul>
<li><strong>Know the feeling</strong></li>
</ul>
<blockquote>
<p>i. On seeing a form with the eye,</p>
<ul>
<li>one investigates the form that is the basis for mental joy,</li>
<li>one investigates the form that is the basis of mental pain,</li>
<li>one investigates the form that is the basis of equanimity.</li>
</ul>
<p>ii. On hearing a sound with the ear,</p>
<ul>
<li>one investigates the sound that is the basis for mental joy,</li>
<li>one investigates the sound that is the basis of mental pain,</li>
<li>one investigates the sound that the basis of equanimity.</li>
</ul>
<p>iii. On smelling a smell with the nose,</p>
<ul>
<li>one investigates the smell that is the basis for mental joy,</li>
<li>one investigates the smell that is the basis of mental pain,</li>
<li>one investigates the smell that is the basis of equanimity.</li>
</ul>
<p>iv. On tasting a taste with the tongue,</p>
<ul>
<li>one investigates the taste that is the basis for mental joy,</li>
<li>one investigates the taste that is the basis of mental pain,</li>
<li>one investigates the taste that is the basis of equanimity.</li>
</ul>
<p>v. On feeling a touch with the body,</p>
<ul>
<li>one investigates the touch that is the basis for mental joy,</li>
<li>one investigates the touch that is the basis of mental pain,</li>
<li>one investigates the touch that is the basis of equanimity.</li>
</ul>
<p>vi. On cognizing a mind-object with the mind,</p>
<ul>
<li>one investigates the mind-object that the basis of mental joy,</li>
<li>one investigates the mind-object that is the basis of mental pain,</li>
<li>one investigates the mind-object that is the basis of equanimity.</li>
</ul>
</blockquote>
<p><a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/4.17-Dhatu-Vibhanga-S-m140-piya.pdf" rel="nofollow noreferrer">Dhātu Vibhaṅga Sutta</a></p>
<ul>
<li><strong>Know that the feels are impermanent so do not cling onto them</strong></li>
</ul>
<blockquote>
<p>If he feels a pleasant feeling,</p>
<ul>
<li>he understands that it is impermanent;</li>
<li>he understands that it is not to be clung to;</li>
<li>he understands that there is no delight in it.</li>
</ul>
<p>If he feels a painful feeling,</p>
<ul>
<li>he understands that it is impermanent;</li>
<li>he understands that it is not to be clung to;</li>
<li>he understands that there is no delight in it.</li>
</ul>
<p>If he feels a neutral feeling,</p>
<ul>
<li>he understands that it is impermanent;</li>
<li>he understands that it is not to be clung to;</li>
<li>he understands that there is no delight in it.</li>
</ul>
<p>If he feels a pleasant feeling, he feels it in a detached manner.</p>
<p>If he feels a painful feeling, he feels it in a detached manner.</p>
<p>If he feels a neutral feeling, he feels it in a detached manner.</p>
</blockquote>
<p><a href="http://www.themindingcentre.org/dharmafarer/wp-content/uploads/2009/12/4.17-Dhatu-Vibhanga-S-m140-piya.pdf" rel="nofollow noreferrer">Dhātu Vibhaṅga Sutta</a></p>
 16612: <p>Yes, you can develop a momentum in meditation. After consistent and prolonged practice with discipline, meditation get's it's momentum. I know this from <em>mantra</em> meditation. You fill your mind with spiritual impressions. In beginning it won't be easy because your miind is not used to meditation. But over time, as you get used to the practice of meditation, it will be easier and easier to start meditating.</p>
 471: <p>Here are some excellent advice given by Ajaan Fuang in "<a href="https://www.accesstoinsight.org/lib/thai/fuang/itself.html#med" rel="nofollow noreferrer">Awareness Itself</a>":</p>

<blockquote>
  <p>§ <strong>"When the meditation goes well, don't get excited. When it doesn't
  go well, don't get depressed. Simply be observant to see why it's
  good, why it's bad. If you can be observant like this, it won't be
  long before your meditation becomes a skill."</strong></p>
  
  <p>§ A young nurse practiced meditation with Ajaan Fuang several days
  running, and finally asked him one day, "Why wasn't today's session as
  good as yesterday's?"</p>
  
  <p>He answered: "Meditating is like wearing clothes. Today you wear
  white, tomorrow red, yellow, blue, whatever. You have to keep
  changing. You can't wear the same set of clothes all the time. So
  whatever color you're wearing, just be aware of it. Don't get
  depressed or excited about it."</p>
  
  <p>§ A few months later the same nurse was sitting in meditation when a
  sense of peace and clarity in her mind became so intense that she felt
  she would never have a bad mood infiltrate her mind again. But sure
  enough, bad moods eventually came back as before. When she mentioned
  this to Ajaan Fuang, he said, "Looking after the mind is like raising
  a child. There will have to be bad days along with the good. If you
  want only the good, you're in for trouble. So you have to play
  neutral: Don't fall in with the good or the bad."</p>
  
  <p>§ A student came to complain to Ajaan Fuang that she had been
  meditating for years, and still hadn't gotten anything out of it. His
  immediate response: "You don't meditate to 'get' anything. You
  meditate to let go."</p>
  
  <p>§ "Don't make a journal of your meditation experiences. If you do,
  you'll start meditating in order to have this or that thing happen, so
  that you can write it down in your journal. And as a result, you'll
  end up with nothing but the things you've fabricated."</p>
  
  <p>§ "You can't plan the way your practice is going to go. The mind has
  its own steps and stages, and you have to let the practice follow in
  line with them. That's the only way you'll get genuine results.
  Otherwise you'll turn into a half-baked arahant."</p>
  
  <p>§ "When the mind's not quiet — that's when its poor and burdened with
  difficulties. It takes molehills and turns them into mountains. But
  when the mind is quiet, there's no suffering, because there's nothing
  at all. No mountains at all. When there's a lot to the mind, it's
  simply a lot of defilement, making it suffer."</p>
</blockquote>

<p>Maybe you can give yourself the flexibility of meditating between 15 to 30 minutes. At the end of it, don't cling to any result/ state, and be observant about why today's session was the way it was. If today's session was not good, it's not because you had failed. It was probably due to some defilement entering the mind. Then that would lead you to identify how the defilement came into the mind. That's more skillful than blaming yourself.</p>
