Crying...
We had a few substitute teachers who dissolved into tears in junior high. The boys in our class were pretty brutal sometimes. I still remember one substitute teacher sobbing in front of the class, proclaiming loudly "You people are the most horrible people I've ever met!!!" I did feel really bad for her, I certainly wasn't a perfect student, but I wouldn't partake in anything that would hurt somebody that badly. Never saw her again, maybe she quit teaching.