The best teacher I ever had taught us physics from age 14 to 18. He was old, wise, kindly and reminded one of Doc from Back To The Future. His style was more that of a university lecturer; he would just talk to the class and write stuff on the blackboard, and if you wanted to listen and take notes, then fine; if you didn't, he wasn't too bothered, as long as you didn't disrupt the students who wanted to learn. If one of the chav kids at the back started fucking around too much, he'd send them out of the class. For the most part, us good kids at the front were interested; we weren't swots, we didn't try too hard, and maybe sometimes it was more interesting to talk about games or cartoons, or doodle in our books, but we respected the guy 'cause he was awesome, and he liked us for that. His lessons were the highlight of the week. It probably helped that it was my favourite subject anyway, and I had a pre-existing interest in it.
One time we were messing around while doing an experiment involving electricity, with power packs that plugged into the mains and gave you a DC 12V rail for your experiments. We gathered up all the packs that weren't being used, and some that our friends were using, and connected them in series, about six of them, to give like 72V*, and started arcing wicked sparks everywhere, singeing bits of paper and melting thin bits of wire. His response to this was to tell us a simplified version of the story of Harry Daghlian [http://en.wikipedia.org/wiki/Harry_K._Daghlian,_Jr.], a Manhattan Project scientist who died from radiation sickness as a result of an accident during an experiment at LANL caused by the flouting of safety regulations.
The incident I'm about to discuss happened shortly after we had left school. Apparently some dickwad kid was being a ****, was asked to leave but refused and talked shit at this teacher, who then grabbed him by the hand and attempted to forcibly remove him. He resisted, and the teacher, presumably feeling years of suppressed anger for all the other little dickwads in the past boiling up into this one moment, simply snaps the kid's finger, breaking it.
The teacher was forced to resign.
[small]* I think voltage is additive in this way, although I may be wrong; it could be current that I'm thinking of.[/small]