[Katsuki just scoffs, and chops through the next potato even faster and harder. Still with that same precision though, which could be intimidating in it's own way.]

It's pretty simple, doon't move so slow and you won't get called out, dumbass.

[Okay but part two of this kid's confrontation has him stopping, glancing over to offer a dangerous look.]

Bet your ass it is. I've got plenty more where that came from too, you damn nerd. You sure you wanna start something with me? I could crush you with one hand. [Not to mention the knife he has in his hand...]