(e.g job interviews, formal situations).
For obvious reasons, I don't swear in kind of situations, but I remember a job interview when the interviewer started to curse. Not at me, but at somebody else on the phone. Needless to say, it was quite akward...
I don't think swearing/cursing is necessary. It could be a way of expression but it doesn't mean you need to say those words when you're angry or anything.
Well, it shouldn't be because languages have enough words to allow us to express things in many ways. Having said that, sometimes I find it hard not to curse, especially if my physical integrity is in danger due to other people's stupidity (not the word I have in mind, but I can't find the right word in English, sorry).
Example: I work in a lab. The other day somebody left a couple of test tubes filled with an acid in an inappropiate place and I almost burned myself. I could've been seriously injured! Obviously, I cursed and yelled at her for some time...