Romen, is this a real question or you just playing around? It's not polite to use profanity with everyone in daily life simply because it's not civil. It's not expected behavior. Of course it's not taboo. People use it all the time. I use it when talking with my good friends, but not with acquaintances, colleagues, and strangers. Do you use ' мат ' with everyone you meet in Ukraine? I doubt it. People pay to watch comedy shows such as Eddy Murphy's, but his show is not shown on public TV, and neither is 'Dexter,' which is broadcast on a 'pay' cable television channel (I love this show, by the way). We see Dexter chopping up people all the time. Should we do it too? It's on TV, why not? :-)

Well, TV series are fiction. I can understand your confusion if this is the only "authentic" English input that you're getting, but in a native-speaking environment it's pretty clear what is real life and what is just fantasy. Even young children get told off by their parents for repeating bad language from TV. We do swear, but nowhere near as much as you might see on TV or in the movies (apart from one or two people we might know). You've given a good example with Dexter: yes, Deb swears like a trooper and that's part of her personality. The other characters - not so much. Eddie Murphy's Raw is classic. I love it. :) Did you notice Samuel L. Jackson's cameo? Anyway, if it was normal to swear as much as Eddie Murphy does on stage, then people wouldn't really clap and cheer him on, would they? Part of the charm of bad language is the idea that you shouldn't say it. One more story... I was in Thailand last month, at a pub with a Welsh colleague. We overheard some guys at a nearby table speaking English, quite clearly. However, one of the guys was dropping in "f***ing" frequently into every sentence, and we couldn't help but laugh. The usage of the swear word was so random and misplaced that it was painfully obvious to us that the guy wasn't a native English speaker, in spite of how well he spoke otherwise.