This actually worked for me in high school. There were two guys always bothering me, untill they sat at my table in class once. Class did not even start yet, they put their seats at my table and started nagging me. I started blankly at them, untill I got overwhelmed by annoyance and slapped one of the guys in the face. The class was chaotic before, and everybody was talking - untill my hand came across his face. Not did I only slap him, but apparently also humiliate since the whole class went silent and then burst into laughter. They never bothered me again.