I swear for emphasis, usually. And when generally annoyed.
I've never understood the mindset behind swearing, to me they are just words, no more corrupting and evil than any other words. For me, classing a means of expression as wrong just doesn't make sense. Besides, some swear words have amusing histories that go back thousands of years, and Fuck is actually the only word in the English language that can be used in any context whatsoever, while still making sense.
So yes, I swear a fair bit, and I don't see why we shouldn't.
Cock juggling, syphilitic fuck heads.