There is a really interesting article in the Science section of the NY Times on swearing and obscenities (you need a free login to read it). I cuss like a sailor at times, ok most of the time, so I found it fascinating... Maybe this is why I do it:
Yet as much as bad language can deliver a jolt, it can help wash away stress and anger. In some settings, the free flow of foul language may signal not hostility or social pathology, but harmony and tranquility.
"Studies show that if you're with a group of close friends, the more relaxed you are, the more you swear," Dr. Burridge said. "It's a way of saying: 'I'm so comfortable here I can let off steam. I can say whatever I like.' "
Evidence also suggests that cursing can be an effective means of venting aggression and thereby forestalling physical violence.
Oh, like when that stupid goddamned asshole in the friggin' Hummer H2 cuts you off because he's the imbecile king of the fucking road with his fucking cell phone stuck to his ear and his fucking head up his fucking ass talking about not a goddamned thing?