Over the course of my 17 years of teaching in Thailand, I've seen many displays of ignorance and just general stupidity by my fellow foreign teachers while at school.
I'll start with my most recent and probably one of my most favorites.
I worked with a middle aged black man that made every effort to remind everyone around him he was black. The foreign teachers routine was to drop our bags off in the office first thing in the morning and then go downstairs for assembly. I always wanted to fuck with him by putting up the Confederate flag on my desk, but seriously couldn't be bothered.
This teacher shows up in the office one morning, drops off his bag with his shirt untucked (meaning he's already walked through the school looking like shit) drops off his bag and myself, him and another male teacher go to the elevator to go down for assembly. While waiting for the elevator to arrive, I pointedly look down his shirt and remind him we're going out in public.
About that time the elevator arrives. We jump in, he unbuckles his belt and pants and starts arranging his shirt. Of course, the elevator stops at the next floor down, where an older female Thai teacher gets on. She sees him tucking his shirt in the front of his pants and gives a gasp.
It was all I could do not to laugh. When we got to the ground floor, the other teacher got me aside and told me I'd be getting a phone call from the agencies management. Sure enough, I get told to remind an adult male that he should have his shirt tucked in and be presentable before he arrives on campus.