When I first read this I never understood why Haejoon was always so aggressive towards Eunyung despite him never really doing anything, but rereading this again, I realize now that this is all a trauma response. The bullying messed him up real bad, so combine that with the fact his first interaction with Eunyung he was lying, and that Eunyung likes to troll...... Not a good combo when your body is conditioned to go into fight mode to protect itself from harassment