Notstalgia
As the past drifts farther and farther away, most people have a natural tendency to focus on only the best parts while glossing over the bad. Hence, nostalgia.
However, there are some people that experience the bizarre inverse of this. They instead exaggerate the bad while forgetting the good. Perhaps you’ve encountered the type? They might appear to be having a blast at a party or event and if asked about it soon thereafter will admit to having had a great time. But then as time goes on, they recall the event less and less fondly - perhaps even to the point of retroactively hating it.
Cynicism? Brain worms? Who knows. The point is, I’ve got a term for this: notstalgia.
You’re welcome.
I am: