This question was inspired by a situation in a role-playing game.
Basically, the character in question had been forced to relocate and live for a good chunk of her childhood in a very bad slum, and it was a miracle that she wasn't a victim herself.
Later, she relocated into another city which, even if it wasn't perfect, looked like paradise in contrast to the hell where she was. Even then, she eventually realised that it's not much of the ideal life either; it was better only by comparing it to her previous city. Upon revisiting the place many years later, she says:
Is there a word for feeling nostalgic for a place you can't wait to leave again? I don't miss this place... But I miss the feelings I had when I lived here.
An example of how I could use a word or an expression to express it:
Friend: How do you feel about this place?
Me: Sad, or rather [the word or expression].
Me: I've had good times here, but it's not what it used to be.