Sort of how others talk about nostalgia, but for me its usually past relationships, even if they ended badly. It's mostly getting obsessed about my first relationship (and the summer that followed) but I also think about others as well to the point of even listening to the same music I did back then. 

I'm not really explaining it all that well, but was wondering if anyone else ever felt the same.

EDIT: Forgot to add that the nostalgia tends to be polarizing for me - is triggering but at the same time makes me feel happy. Is that strange or does anyone else feel the same way?