For example, I hate the standard kdrama trope of the Cinderella story where the poor girl and/or her family is saved by the rich guy, who treats her badly throughout the series, but it's ok, because he's angsty and he loves her, so he can treat her badly as long as she gets the cute guy and a better financial/social position.

It depends for me. I am perfectly fine with "he treats her badly" when it is four things (have to be at the same time):

1) Not TOO badly, just cold or generally the not kindest of persons to everyone (but with a good reason of unhappy family or something)
2) At the start of relationship. He doesn't know her and doesn't love her yet. he treats everyone the same, men and women.
3) When the girl is no push-over (as in she thinks just because he rich he can do this). She is just a kind person to everyone.
4) He changes as the relationship progress (the most important point). He becomes a putty in her hands.

The examples: "Lovers", "Lovers in Paris", "Beautiful days"

I dislike:

1) When bad treatment is presented as cute, as in "Hong Gil Dong"
2) Or where he is indeed too OTT and doesn't seem to want to change(like "Que Sera Sera")

"Goong" is a bit borderline because Shin changes come about only in the last two episodes. but it still passes with me.

But in general, I think I am an emotional fan. :D