you were on a mission with the rest of your classmates and Mr. Aizawa put you guys into pairs, unlucky you got paired with bakugou which wasn't bad but probably wasn't good either, since if he was in a bad mood he would blow you and the villain up regardless of whether you did something or not. So you decided to stay quiet for the time being to not bring up the chances but while you were walking with bakugo he says "damn your really boring say talk damnit." that was a straightforward insult.