At various times when I've gotten a shorter than normal haircut, people will say "Nazi." As a blond, blue-eyed, pale American, that hurts! Although I'm not actually being discriminated against, now I totally know what discrimination is like.
Another time, my homeroom teacher in high school, apropos of nothing, on the last day of school asked me if I were Swedish. Despite my non-Swedish name, the fact that I was from the town I was in, and I'd never worn any sort of national Swedish costume.
Yorgen vorgen I was angry!