Haeju
A city in North Korea that also sounds like you're calling someone a piece of garbage. Koreans use it as a greeting, but it's really just a way to be rude.
I said 'Haeju' to my teacher and got a pop quiz.
My cousin used 'Haeju' as a nickname and now he's stuck with it.
I yelled 'Haeju' at my brother and now he won't talk to me.