You can't give up on children, you know? If the teachers give up hope on the little shits, what chances do they have in life? I tend to find (and this isn't a surprise to anyone, I'm sure) that the really bad kids usually have really bad parents, so teachers are their last line of hope.
For example, the 10 year old kid i mentioned - his sister is in a mental institution, his mother is pregnant by a man who beats her almost daily... we must never give up!

A.