user11366: I've read several reports of people remembering past lives. In many cases, in their current life they tend to have a very similar personality, repeat many of the same life patterns and often have many of the same interests they had in their previous life. This would suggest that we incarnate into lives which were similar to our past life, repeating similar karmic patterns.
However, I have also read many sources which claim that we incarnate into life situations which are the complete reverse of our previous life in order to experience the karma 'from the other side' of the situation. For instance, if you were an abuser in a previous life, many claim that in this life you would be the victim of an abuser who was your victim in your past life.
The two paradigms seem rather mutually exclusive. I was wondering if Buddhism could help shed some light on to this.

user-1: 
Do we reincarnate into similar or polar-opposite lives

In MN 41 - Saleyyaka Sutta: The Brahmans of Sala, the Buddha is wandering in the Kosalan country with a large group of monks when he arrives at a village named Sala. Here a brahmin householder from the village hears about the Buddha being in Sala and want to ask him about why beings fare as they do after death. The brahmin householder asks the Buddha:

"... Master Gotama, what is the cause and condition why some beings here, on
  the breakup of the body, after death, are reborn in a state of misery, in
  a bad destination, in the lower world, in hell? And what is the cause
  and condition why some beings here, on the breakup of the body, after
  death, are reborn in a good destination, in a heavenly world? ...”.

The Buddha then answers:

“... Householders, it is by reason of unrighteous conduct, conduct
  not in accordance with the Dhamma, that some beings here, on the breakup of the body, after death, are reborn in a state of misery, in a
  bad destination, in the lower world, in hell. It is by reason of righteous
  conduct, conduct in accordance with the Dhamma, that some beings
  here, on the breakup of the body, after death, are reborn in a good destination,
  in a heavenly world ...”.

The brahmin householders explain that they do not understand the phrase "unrighteous / righteous conduct and conduct not in accordance with the Dhamma" and ask the Buddha to further expound on his teaching.
The Buddha then explains in details what unrighteous and righteous conduct in accordance with the Dhamma is:


"... Householders, there are three kinds of unrighteous bodily conduct,
  conduct not in accordance with the Dhamma. "
"There are four kinds of unrighteous verbal conduct, conduct not in accordance with the Dhamma. "
"There are three kinds of unrighteous mental conduct,
  conduct not in accordance with the Dhamma ..."


The Buddha continues to explain unrighteous bodily conduct:

“... And how, householders, are there three kinds of unrighteous
  bodily conduct, conduct not in accordance with the Dhamma? Here
  someone kills living beings; he is murderous, bloody-handed, given
  to blows and violence, merciless to living beings. He takes what is not
  given; he takes by way of theft the wealth and property of others in
  the village or forest. He commits sexual misconduct; he has intercourse
  with women who are protected by their mother, father, mother and
  father, brother, sister, or relatives, who have a husband, who are protected
  by law, and even with those already engaged. That is how there
  are three kinds of unrighteous bodily conduct, conduct not in accordance
  with the Dhamma ...".

Then unrighteous verbal conduct:

“And how, householders, are there four kinds of unrighteous verbal
  conduct, conduct not in accordance with the Dhamma? Here
  someone speaks falsehood; when summoned to a court, or to a meeting,
  or to his relatives’ presence, or to his guild, or to the royal family’s
  presence, and questioned as a witness thus: ‘So, good man, tell what
  you know,’ not knowing, he says, ‘I know,’ or knowing, he says, ‘I do
  not know’; not seeing, he says, ‘I see,’ or seeing, he says, ‘I do not see’;
  in full awareness he speaks falsehood for his own ends, or for
  another’s ends, or for some trifling worldly end. He speaks maliciously;
  he repeats elsewhere what he has heard here in order to divide [those people] from these, or he repeats to these people what
  he has heard elsewhere in order to divide [these people] from those;
  thus he is one who divides those who are united, a creator of divisions,
  who enjoys discord, rejoices in discord, delights in discord, a speaker
  of words that create discord. He speaks harshly; he utters such words
  as are rough, hard, hurtful to others, offensive to others, bordering on
  anger, not conducive to concentration. He engages in idle chatter; he
  speaks at the wrong time, speaks what is not fact, speaks what is useless,
  speaks contrary to the Dhamma and the Discipline; at the wrong
  time he speaks such words as are worthless, unreasonable, immoderate,
  and unbeneficial. That is how there are four kinds of unrighteous
  verbal conduct, conduct not in accordance with the Dhamma.

Then unrighteous mental conduct:

“... And how, householders, are there three kinds of unrighteous
  mental conduct, conduct not in accordance with the Dhamma? Here
  someone is covetous; he covets the wealth and property of others thus:
  ‘Oh, may what belongs to another be mine!’ Or he has a mind of ill
  will and intentions of hate thus: ‘May these beings be slain and slaughtered,
  may they be cut off, perish, or be annihilated!’ Or he has wrong
  view, distorted vision, thus: ‘There is nothing given, nothing offered,
  nothing sacrificed; no fruit or result of good and bad actions; no this
  world, no other world; no mother, no father; no beings who are reborn
  spontaneously; no good and virtuous ascetics and brahmins in the
  world who have themselves realized by direct knowledge and declare
  this world and the other world. That is how there are three kinds of
  unrighteous mental conduct, conduct not in accordance with the
  Dhamma ..."

The Buddha finishes expounding on these unrighteous types of conduct by saying:

"... So, householders, it is by reason of such unrighteous conduct,
  such conduct not in accordance with the Dhamma, that some
  beings here on the breakup of the body, after death, are reborn in a
  state of misery, in a bad destination, in the lower world, in hell ...".

The Buddha then continues to expound upon the three kinds of righteous bodily conduct, conduct not in accordance with the Dhamma. I will not refer to them here as they are opposites of the above mentioned Dhamma and can be found in the sutta. The Buddha then ends these three types of righteous conduct by saying:

"... So, householders, it is by reason of such righteous conduct, such conduct in
  accordance with the Dhamma that some beings here, on the breakup
  of the body, after death, are reborn in a good destination, even in a
  heavenly world ...".

So to sum up on your question, the Buddha teaches that it is our actions done by body, speech or mind that play a part in the rebirth destination. The Buddha teaches what to do in order to be reborn both in the lower realms and in the heavenly realms. This is of course only one sutta there are other suttas as well. I chose this sutta as I think the Buddha here gives a very clear and detailed exposition on conduct in relation to the Dhamma and rebirth destination.
Hope this helps. If you have any questions to what I wrote feel free to ask. 

user-1: No matter how you slice it, Buddha said we have been in every situation many times over.  In one sutta said when seeing a wealthy man indulging in all fine things in life and in another sutta crippled man lying in the gutter, we have all been there.  For this reason, it is enough to be tired of samsara.
It is reasonably to assume we have been in every situation and every world many times (except for world of sutavassa-world for non-returners.)

11366: <p>I've read several reports of people remembering past lives. In many cases, in their current life they tend to have a very similar personality, repeat many of the same life patterns and often have many of the same interests they had in their previous life. This would suggest that we incarnate into lives which were similar to our past life, repeating similar karmic patterns.</p>

<p>However, I have also read many sources which claim that we incarnate into life situations which are the complete reverse of our previous life in order to experience the karma 'from the other side' of the situation. For instance, if you were an abuser in a previous life, many claim that in this life you would be the victim of an abuser who was your victim in your past life.</p>

<p>The two paradigms seem rather mutually exclusive. I was wondering if Buddhism could help shed some light on to this.</p>
 -1: <blockquote>
  <p>Do we reincarnate into similar or polar-opposite lives</p>
</blockquote>

<p>In <em>MN 41 - Saleyyaka Sutta: The Brahmans of Sala</em>, the Buddha is wandering in the Kosalan country with a large group of monks when he arrives at a village named Sala. Here a brahmin householder from the village hears about the Buddha being in Sala and want to ask him about why beings fare as they do after death. The brahmin householder asks the Buddha:</p>

<blockquote>
  <p><em>"... Master Gotama, what is the cause and condition why some beings here, on
  the breakup of the body, after death, are reborn in a state of misery, in
  a bad destination, in the lower world, in hell? And what is the cause
  and condition why some beings here, on the breakup of the body, after
  death, are reborn in a good destination, in a heavenly world? ...”.</em></p>
</blockquote>

<p>The Buddha then answers:</p>

<blockquote>
  <p><em>“... Householders, it is by reason of unrighteous conduct, conduct
  not in accordance with the Dhamma, that some beings here, on the breakup of the body, after death, are reborn in a state of misery, in a
  bad destination, in the lower world, in hell. It is by reason of righteous
  conduct, conduct in accordance with the Dhamma, that some beings
  here, on the breakup of the body, after death, are reborn in a good destination,
  in a heavenly world ...”</em>.</p>
</blockquote>

<p>The brahmin householders explain that they do not understand the phrase <em>"unrighteous / righteous conduct and conduct not in accordance with the Dhamma"</em> and ask the Buddha to further expound on his teaching.
The Buddha then explains in details what unrighteous and righteous conduct in accordance with the Dhamma is:</p>

<blockquote>
  <ul>
  <li><em>"... Householders, there are three kinds of unrighteous bodily conduct,
  conduct not in accordance with the Dhamma. "</em></li>
  <li><em>"There are four kinds of unrighteous verbal conduct, conduct not in accordance with the Dhamma. "</em></li>
  <li><em>"There are three kinds of unrighteous mental conduct,
  conduct not in accordance with the Dhamma ..."</em></li>
  </ul>
</blockquote>

<p>The Buddha continues to explain <em>unrighteous bodily conduct</em>:</p>

<blockquote>
  <p><em>“... And how, householders, are there three kinds of unrighteous
  bodily conduct, conduct not in accordance with the Dhamma? Here
  someone kills living beings; he is murderous, bloody-handed, given
  to blows and violence, merciless to living beings. He takes what is not
  given; he takes by way of theft the wealth and property of others in
  the village or forest. He commits sexual misconduct; he has intercourse
  with women who are protected by their mother, father, mother and
  father, brother, sister, or relatives, who have a husband, who are protected
  by law, and even with those already engaged. That is how there
  are three kinds of unrighteous bodily conduct, conduct not in accordance
  with the Dhamma ..."</em>.</p>
</blockquote>

<p>Then <em>unrighteous verbal conduct</em>:</p>

<blockquote>
  <p>“And how, householders, are there four kinds of unrighteous verbal
  conduct, conduct not in accordance with the Dhamma? Here
  someone speaks falsehood; when summoned to a court, or to a meeting,
  or to his relatives’ presence, or to his guild, or to the royal family’s
  presence, and questioned as a witness thus: ‘So, good man, tell what
  you know,’ not knowing, he says, ‘I know,’ or knowing, he says, ‘I do
  not know’; not seeing, he says, ‘I see,’ or seeing, he says, ‘I do not see’;
  in full awareness he speaks falsehood for his own ends, or for
  another’s ends, or for some trifling worldly end. He speaks maliciously;
  he repeats elsewhere what he has heard here in order to divide [those people] from these, or he repeats to these people what
  he has heard elsewhere in order to divide [these people] from those;
  thus he is one who divides those who are united, a creator of divisions,
  who enjoys discord, rejoices in discord, delights in discord, a speaker
  of words that create discord. He speaks harshly; he utters such words
  as are rough, hard, hurtful to others, offensive to others, bordering on
  anger, not conducive to concentration. He engages in idle chatter; he
  speaks at the wrong time, speaks what is not fact, speaks what is useless,
  speaks contrary to the Dhamma and the Discipline; at the wrong
  time he speaks such words as are worthless, unreasonable, immoderate,
  and unbeneficial. That is how there are four kinds of unrighteous
  verbal conduct, conduct not in accordance with the Dhamma.</p>
</blockquote>

<p>Then <em>unrighteous mental conduct</em>:</p>

<blockquote>
  <p><em>“... And how, householders, are there three kinds of unrighteous
  mental conduct, conduct not in accordance with the Dhamma? Here
  someone is covetous; he covets the wealth and property of others thus:
  ‘Oh, may what belongs to another be mine!’ Or he has a mind of ill
  will and intentions of hate thus: ‘May these beings be slain and slaughtered,
  may they be cut off, perish, or be annihilated!’ Or he has wrong
  view, distorted vision, thus: ‘There is nothing given, nothing offered,
  nothing sacrificed; no fruit or result of good and bad actions; no this
  world, no other world; no mother, no father; no beings who are reborn
  spontaneously; no good and virtuous ascetics and brahmins in the
  world who have themselves realized by direct knowledge and declare
  this world and the other world. That is how there are three kinds of
  unrighteous mental conduct, conduct not in accordance with the
  Dhamma ..."</em></p>
</blockquote>

<p>The Buddha finishes expounding on these unrighteous types of conduct by saying:</p>

<blockquote>
  <p><em>"... So, householders, it is by reason of such unrighteous conduct,
  such conduct not in accordance with the Dhamma, that some
  beings here on the breakup of the body, after death, are reborn in a
  state of misery, in a bad destination, in the lower world, in hell ..."</em>.</p>
</blockquote>

<p>The Buddha then continues to expound upon the three kinds of <em>righteous bodily conduct, conduct not in accordance with the Dhamma</em>. I will not refer to them here as they are opposites of the above mentioned Dhamma and can be found in the sutta. The Buddha then ends these three types of righteous conduct by saying:</p>

<blockquote>
  <p><em>"... So, householders, it is by reason of such righteous conduct, such conduct in
  accordance with the Dhamma that some beings here, on the breakup
  of the body, after death, are reborn in a good destination, even in a
  heavenly world ..."</em>.</p>
</blockquote>

<p>So to sum up on your question, the Buddha teaches that it is our actions done by <em>body, speech or mind</em> that play a part in the rebirth destination. The Buddha teaches what to do in order to be reborn both in the lower realms and in the heavenly realms. This is of course only one sutta there are other suttas as well. I chose this sutta as I think the Buddha here gives a very clear and detailed exposition on conduct in relation to the Dhamma and rebirth destination.</p>

<p>Hope this helps. If you have any questions to what I wrote feel free to ask. </p>
 -1: <p>No matter how you slice it, Buddha said we have been in every situation many times over.  In one sutta said when seeing a wealthy man indulging in all fine things in life and in another sutta crippled man lying in the gutter, we have all been there.  For this reason, it is enough to be tired of samsara.<br>
It is reasonably to assume we have been in every situation and every world many times (except for world of sutavassa-world for non-returners.)</p>
