Never understood why lecturers/professors take so much offense. Well if people are throwing paper air planes in the air you should be convinced that either everyone in the class is totally disinterested in math(which is impossible) or something is wrong in the way you teach.
Thinking back on those lectures, they were a bit on the dry side and as there was a lot of restlessness during the lectures.
Also the paper planes had started to appear in earlier lectures and the prof did pretty much ignore them.
I think it in this instance it was the plane crashing into the blackboard (and making a pretty loud thud) only inches from his left ear that finally made him snap.
I think its a politeness thing really - 9 times out of 10 the lecturer does not want to be there, rehashing the same boring old material again and again, and would much rather be working on their latest project. But they have to be there - you as the young student don't. If you are uninterested, leave. If you find the presentation boring, empathise.
