I'm a passionate guy; this I'll admit this right now. I wear my heart on my sleeve and I'm very emotional. It comes from my ADHD, my parents, and a lifetime of putting up with people pushing my buttons. So I admit, I swear a lot around my friends, family, and even coworkers when we're in the office; swearing's my catharsis against the inanity, the stupidity, and the repetition of my day to day life. If I didn't swear at least once or twice in my sentences, I swear I'd go crazy.
That's not to say I don't show restraint or patience. I know well enough to stay professional when I'm around clients or out in public, and I watch my language around my dear grandmother, because she's the reason I try to be a good person and all. Oh, and I especially watch my language around what I think are relatively family-friendly websites like this forum. Wouldn't want to offend a kid.