I think it's interesting how swear words can seep into the vernacular, or how, vice versa, words that were once part of the vernacular can be repurposed as swear words.
I remember watching the film Easy A at twenty years old and being absolutely baffled at the shocked reaction to Olive calling another character a twat. I had always thought of it as a very mild term, and had used it right through my childhood. "Don't be a twat", "he's a bit of a twat", "wait until you hear about the twattery I had to put up with today" etc. I considered it no more offensive than "idiot" or "fool", and couldn't understand why they were acting like Olive had called the other girl a cunt in school or something.
Eventually I discovered that they mean the same thing, and to Americans are apparently equally bad. I was stunned.
Interestingly, the attitude I had absorbed about the word "cunt" was that it was totally unacceptable and the worst of all words if you used it against a woman . . . but in the hands of a man using it against another man (who didn't really mean him any harm) it was just extra colourful language and was therefore acceptable. The man also had to have a proven track record of No Sexist Attitudes Against Women for me to okay its use.
I couldn't even tell you where I formed this belief, but I'm surprised to find I mostly still hold it. Funny how people are.