I'm offended by them in public. You need to watch your mouth when you're in public because there could be kids around, people who could be offended by your language, or whatever.
I swear around my friends, more so with my friends at school, and rarely around my family. I never swear in front of my grandparents, except one time I dropped the F-bomb and it was a ridiculous story lol.
Honestly though, I'll drop something and be like "dammit" in front of my dad, and sometimes he'll still be like "watch your mouth". I think it's funny at this point because really, I'm 21 and don't live with him and what is he gonna do?

I try to respect them though you know? Makes up for all the bad karma from playing the PENIS! game with my friends in the mall parking lot in junior high.