I once knew a Mormon who prided himself on never swearing. One day, I was helping him with his car, and he was taking a tyre off, and he trapped his fingers in the tyre rim.
He screamed "fuck!!!" and I couldn't help smiling. I was sorry for my friend's fingers but I saw the funny side.
The moral of the story is: save your big guns for bad days. If you use the f-word every day or hour, what will you say when the shit really hits the fan?