Everyday phrases/idioms with racial overrtones?

When I was in my early 20s, I had a bad habit of saying something like "Come on, boy" among friends and co-workers. No idea where it originated. I said it to a guy at my blue-collar job where I worked during college. He was many years older and was a somewhat angry black guy. He looked at me as if he might kill me. Quit saying that on the spot.