Eww. Bad author. Cheap author.
The "hipster" friend, Eppy, seemed like an okay person at first. Like, a clear and obvious poser in terms of art and intellectualism, but that didn't make him a necessarily bad person. And honestly, Ha Sieun seemed like a bit of a jaded person. It was obvious from the beginning that Ha Sieun didn't actually push Eppy, but I was hoping that it was just a genuine, mutual misunderstanding. Like maybe they were arguing and Eppy slipped and mistakenly thought that Ha Sieun pushed him.
But making Eppy the clear and straightforward antagonist, "bad guy", seemed like such a cheap move from the author. It gives an easy pass for Ha Sieun to be "redeemed" even though she hasn't actually changed her attitude. The flashback shows that she was still rubbing in Eppy's face the fact that she was accepted to the school and he wasn't.
What I'm ultimately saying is I don't like it when characters feel cheap, and this felt cheap.