What makes you get up and leave?

[Angrboda]

Or how about when the first movie has two people get together in love, then the sequel has them broken up just so they can get back together again, as if it's going to be just as magical as the last time.

I think that reflects the very real reality that drama is largely character driven, so when you've constructed a set of well-liked characters and people have already invested in them, it's hard to throw away that investment and try to build anew from the ground up. It's a human thing.