What do you (gay men) feel when people use the term faggot as a slang term

I'm just asking out of curiosity really. The word faggot is, as I'm sure you know, used as an insult to gays. But it's also used as an insult to non-gays. How do you feel when you hear someone calling someone else a faggot?For example, let's say you're on a train and 2 friends are sitting across from you. They get into a bit of an argument and one of them says "shut up faggot". Would you be offended by this?