Though I don't swear a LOT, I'll use coarse language when what I'm saying needs that extra emotional punch. If I think something is really, REALLY stupid, for instance, I won't hold back from calling it "f*cktarded," in the interest of efficient speech (it's a lot quicker and clearer than saying "really, REALLY stupid"). But I tend not to swear TOO much, just so the words will have the full impact when used and not be dulled by repetition.
But when I'm in a "mood," I become very creative with my language, so I can curse as much as I d*mn-well please and not worry about repeating myself. I've said things in the heat of anger that would make a sailor with tourette's syndrome blush.