It doesn't upset me at all. I don't like the C word, when used as an insult, as I see that as very misogynistic (the idea that a very personal part of the female anatomy is seen as the very worst thing that someone can be called) , although I know many who disagree. For me it's far worse when people say 'I never usually use that word, but in this case . . .' as that just compounds the felony.
The word that makes me roll my eyes, though, is 'sh*t'. It's used so lazily - does it mean 'poor', 'awful', 'not very good'? Can one be it, talk it, think it, look like it, or what? I dislike imprecise speech, and think that whereas f*ck means what it says, sh*t is such a loosely used word that I find it far more offensive.