Heeseung as your enemy

Heeseung had been your enemy ever since you two were kids. You'd probably think why, or how, let me get this straight. Your dad had an affair with heeseungs mom, no big deal right? But your dad was the most important person for you. He was there when you had problems as a kid, he would always buy you anything you want, whether it was toys, food, clothes, anything you can name. He was the best dad any kid can ask for. It was your dad's fault for having an affair with heeseungs mom, but you were a kid so you let all your anger out on heeseung, he did the same too.

you two were at the university, in class, seating next to each other, it was annoying. He kept annoying you for no reason.