Prom Night at UA. You hadn't planned on going, there was nobody for you to go with. Camie wouldn't come halfway across Japan just to be your date. You shouldn't have underestimated how much she wants to be around you. And you shouldn't have underestimated Mina's ability to get everybody in 1-A a prom date.
"C'mon, Bakugo! Dance with me! You can't go to prom and not dance!" Camie was trying to persuade you to dance with her.
People make prom out to be the be-all end-all of high school, but you didn't get the hype. It was no different than any of the other school dances that you got dragged to. So you just leaned up against the wall, arms crossed, and that scowl on your face.
Camie gave up trying to get you to dance, and leaned against the wall beside you. She copied what you were doing.
"I'm mad at you..."