I swore like a sailor once I learned them in fifth grade. Then I realized how dumb it sounded to say them so often and it gradually died down to the point where some of my new friends were convinced that I don't swear at all. I'd have to say the one I use the most is bullshit, mainly because me and my friends bullshit all our assignments at the last minute.
One of my obsessive-compulsive tendencies is an aversion to strong lanuage. This makes writing stories tricky at times because the characters do not always have such misgivings. It's not so bad in a comedic setting, though, because I can work self-censorship in as part of a gag.