Poll
61%
33%
6%
It depends on the context. I've always been of the opinion that using swear words in general conversation denoted a lack of vocabulary, and therefore a lack of intellect. On the other hand, cursing at a moment of pain/extreme surprise/anger is more acceptable, since it's being brought out suddenly, generally when you're off guard.
This isn't a hard and fast rule, but it seems to be consistent with what I've encountered in my life so far. (With the exception of environments where cursing is used in general speech... there, you tend to get immune to the effects, and it slips out easier. High school, for instance...)
I've worked in environments ranging from a machine shop to a construction site to bartending to auto mechanic to high tech office. I've found that generally, along the way, the higher I've gotten in my income level the less I hear swearing. That's just my view, though...