Obscenity is in the mind of the beholder, so this is a question of personal taste. Some of us are more lenient than others.
I like to take the orginal stance the FCC took when Bono said "Fucking excellent" or some such on an awards show: when used as an interjection, it's not obscene; when used as a command, it is.
Usage plays a lot into it. Is the person calling names or just using expletives? Another "test" is whether it is demeaning others. The final test is, can you stand it for another 5 minutes? If not, freeze them and explain that such language isn't welcome.
-Throbblefoot