Why teachers are so stressed...

I was in the middle of this conversation bout primary & secondary schools' teachers. Some of my friends have taken alot of creative punishments by their teachers. Something such as, slap in faces, kneeling, repeating an act of which that teacher thought was misdone or funny case where one would have to say thank you to everyone as a punishment when one is caught late to class. And why are teachers so stress which lead to the invention of all these "cruel" punishments on poor students? Huhuhu~ Erm I think I have found the answers.
1. Let see what he did when he's asked to expend an algrebiac equation

2. I salute him!