John Kimble (Arnold Schwarzenegger) is a charlatan, a cop posing undercover as a teacher to find a drug lord's ex-wife. He loses his temper easily and lets violence descened on the school. That's what we'd call a bad teacher. But there's some good in the big lug. He's got a ferret and he brings it to class. That's pretty cool. And some of his teachings (how to insist something is not a tumor, and his delicate way in finding out who is your daddy and what did he do) are more ingrained in us than the Pledge of Allegiance.