There's nothing wrong with swearing in a job interview. Just ask Oiler fans how they feel about Robbie Schremp.
Fotze brought up the Carlin quote where he says it's wrong to say the word but it's okay to do the deed. There's another completely hypocritical aspect to swearing in addition to that: words that mean the exact same thing are perfectly fine to say (even for a 3-year old), but the arbitrarily chosen "swear word" is taboo.
Example:
Poop. Poop is a pretty innocent word.
sh*t, however, while meaning the exact same thing, is frowned upon. There are no uses of the word 'sh*t' that couldn't be replaced with the word 'poop' that change the meaning (that I can think of; or very few), so they are functionally identical. So why the difference?
I submit this for your consideration: I think we need swear words. I think it's important for us to be able to vent our frustrations by saying something that's socially unacceptable, or at least socially unpleasant. Kids do it to feel rebellious -- something I think they _need_ an outlet for. Adults do it around adults because "oh, poop" just doesn't carry much rhetorical weight, while "oh sh*t" sounds like the person is in a far more significant bind. By saying something that's considered unpleasant, we instantly convey an attitude: that my situation is such that I want to (or inadvertently) offend conventions. Someone who swears quite often conveys less emotion when swearing because these conventions obviously mean little to them, while someone who rarely swears conveys a great deal with a simple "sh*t!".