A character's memory of a defining event overlooks or outright omits key details to better suit their narrative.

Syndrome's memory of Mr Incredible "rejecting" him - The Incredibles. He, a child with no experience in heroics, was outright getting himself involved in an active crime scene with a literal bomber, but in his memory of that night, Bomb Voyage isn't even there. He frames it as Bob coldly telling him to get lost, when in reality Bob had an extremely good reason to tell him, "For the love of God, get out of here." Also, a short line from Bob earlier in the day mentioned he'd been nice to Buddy numerous times before, so this wasn't even a new thing, but was in fact clearly the latest and most egregious event of Buddy being an overly eager fanboy.

Bowler Hat Guy / Mike Yagoobian's "origin story" - Meet The Robinsons. Because it's easier to convince yourself that you were the victim of ongoing bullying and rejection after one bad event, than to admit that there were actually plenty of people who were trying to treat you with kindness and that you wasted your entire life wallowing in misery and self-pity.

Friedrich Nietzsche writing on this very phenomenon - Beyond Good and Evil