This movie is not for those who are offended by curse words or violence or social/political incorrectness.
But then, the movie is called "Seven Psychopaths", isn't it? Shouldn't that suggest that the film probably wouldn't be enjoyed by those who are easily offended by such things? Those are the sorts of things psychopaths might be likely to indulge in...right?
Sadly, the content of most of the 1- and 2-star reviews seems to suggest that quite a few people didn't make that inference. "I stopped watching because of the repeated use of the f-word." "I couldn't continue watching after they called the one lady the n-word." Etc. etc... These are horrible people we're watching, folks. Of course they're going to offend us.
Oh well, I thought the movie was great. But I'm not about to be like so many other reviewers and list all of the plot details. Spoilers are no fun.
This is a dark comedy. It's certainly not meant to appeal to common sensibilities; most often it's meant to satirize them. It also (quite amusingly) satirizes itself and the general "gangster/revenge drama" genre which it very much knows it fits into (mostly). The movie laughs at itself, it's intentionally absurd at times, but if you stick around and pay attention the payoff is there to be enjoyed.