I love swear words and I never curbed my tongue too much when my kids were young. Okay, so what if we call it potty mouth. Sometimes FUCK is the only appropriate response. Granted, I don't like hearing my favorite word overused because some punk likes to use it in every other word of their sentence but swearing doesn't usually offend me.
Someone once exclaimed "You are a cunt," to me.
Instead of getting offended I said, "I have my moments. But why do you think so?"
I mean... come ON! I'm usually a very nice person. Pretty laid back. Strangers don't know me well enough and they certainly haven't spent enough asshole time with me to call me a cunt so I chalk it up to their ignorance rather than being offended.

My parents never said, "If you can't say something nice, don't say anything at all." In fact, my father often said, "If you can't say something nice, come sit next to me." Perhaps that's the Irish humor. :D