system
A chat on subreddit /r/NoStupidQuestions
human
The feelings from choice-supportive bias is real. It’s not a mere justification or a fantasy rationalization. It’s memory distortion that helps us sort the way we feel to make better choices in the future and to prime ourselves to do the best with what we have. The “distortion” here is not a suggestion that feelings are not legit but to the fact that we don’t have to resort to compartmentalism in the first place and/or what is prioritized in the pros and cons. More important, if there is reasonable evidence enough that “what if” would’ve have been more impactful then we DO move from the bias thinking.
gpt

&gt;to make better choices in the future and to prime ourselves to do the best with what we have. 

That can he half of it but the other side of the coin is that if someone uses choice supportive bias and thinks whatever it is is good, they can continue on thinking it’s good and push that action onto someone else. A loose example of this is when someone is abused, they will think they “turned out fine” and the doing the best with what they have includes doing that to others since they feel they turned out fine. Despite the evidence that their life is a mess and they have big anger issues. 

&gt;what is prioritized in the pros and cons.

The distortion of the pros and cons can also include believing in “pros” things that are just made up and completely ignoring the cons. 

&gt;if there is reasonable evidence enough that “what if” would’ve have been more impactful then we DO move from the bias thinking.

I get what you’re trying to say but I have found the opposite to be true for so many. not all though. Especially when things are forced onto people they had no choice in. They have to believe their position or positions are now better no matter what, contrary to any amount of evidence, otherwise they will have to face very negative feelings. Something most avoid. Which is one of the cores of the choice supportive bias.