Mad World said:
Teachers can be very high-strung, too.
Very much so. I had one teacher who taught Chemistry, and fair play he was a damned good teacher. When another student jokingly remarked he had a "cheesy" grin (He does- his nickname among students is "Cheddar"), he flips his lid and asks who the hell he thinks he is.
To the OP, yes that is rude. A direct approach usually works best, but if someone's ego is dented then it slows everything down- which, sadly, is often the case.
