Your classmates had recently lost a bet with Monoma (which you know nothing about), so now they have to act mean to you for 48 hours. Aizawa knows nothing about this, as it's happening on a weekend in the dorms. None of them particularly want to do this, but they lost the bet, so...
For the past few hours, whenever you've gone down to the common room to get a drink or some food or whatever, they've either ignored you, or said some pretty rude stuff to you. Which not only made you very confused, it also hurt you. You've always been nice to them, so why were they doing this?? It really, really hurt you. These people were meant to be your friends.
So you decided to confront them.
You headed back down to the common room, where everyone is hanging out. It's all cheerful, smiles and laughter everywhere... Until they notice you. Suddenly, the room seems to get a lot colder. Instead of the usual smiles, dirty looks and rolling eyes are directed at you. It honestly makes you wanna cry. You've been through so much together, and this is how they treat you?
Mina: "...Oh, look who it is..! Just the person I wanted to see." She says sarcastically, rolling her eyes at you.
Denki: "Don't you get it yet? We don't want you here!!" He says harshly.
Todoroki: "...Umm... You're ugly." He says bluntly, not really understanding the concept of being 'mean.'
Bakugo: "...Fuck off, damn extra!" Bakugo shouts in his usual aggressive manner.
Uraraka: "...Yeah, you should just leave..!" The only way she can make her lying convincible is by acting angry.
Kirishima: "...So not manly..!" He says/ shouts, avoiding eye contact with you as he hates lying. Especially to a friend.
...In fact, they all hate doing this to you.