... but I need to get it out of the way. I'm going to ramble a bit, to establish where I am coming from, but my main point is at the end.
I am generally pretty tolerant of other people's musical preferences. There are some bands that I really cannot fucking stand, but I undetand why other people would like them. I may strongly distrust your opinions on music and think you have very little knowledge of what actually makes good, interesting music (usually this is for the Hot Topic/MTV2/Warped Tour sad sack screamy stuff), but I do not begrudge you your choices.
I have the right to say something is awful, but there are very few bands I think are devoid of talent enough to warrant a serious suspicion of someone's intelligence for liking. If you like FATA, Hawthorne Heights, Creed, Britney Spears, Taking Back Sunday, Linkin Park, whatever... I don't care. I think it all sucks, but I can see why someone would listen to it. There are a few (Slipknot, Master P) though, that I feel there is something wrong with you if you like them.
Being the classic mixtaper that I am, I hope that people into those bands are very early in their musical journeys. When I was young, I liked some stuff that is vastly far removed from anything I would consider good now. Here, I'll admit to a few things- In middle school, I liked Garth Brooks. I liked Creed's first album when I was like 16. I was into Dave Matthews first couple of albums. More recently, I even had a fling with Taking Back Sunday's first album (although that was a really brief). I still sort of appreciate the kitsch of Danish techno-pop group Aqua.
But I kept an open mind, figured out some stuff that was actually good, my tastes matured, and I outgrew those bands, and plenty of others have been left in the dust. I got more into older music, and found different avenues of learning about newer bands. I hope people with what I consider crappy taste can grow up and do the same, but even if they do not, I am sure they are fine people, and would have no problem being their friend if we had something else to talk about. I know a LOT of the stuff I listen to is not very accessible, and despite large fanbases, most people will never like Sufjan Stevens, or The Blood Brothers, or Youth Of Today, or The Stooges, or David Allan Coe.
So my point of all this rambling was to hopefully establish that I am not trying to ride highhorse here, and I don't want to be pretentious, and though I will critique music, it is not in my nature to judge PEOPLE.
Now, on to what I REALLY want to say...
If you do not like Johnny Cash, there is a good chance I want nothing to do with you. You don't have to love him, you don't have to be very familiar with his work. I get annoyed when all people can talk about is his cover of NIN or Depeche Mode (moreso when they claim to really like Johnny Cash but that's all they know), but even if that's all you've heard and you like it, or you're just like "yeah, I think Johnny Cash is OK," then that's good enough.
But if you actually dislike Johnny Cash's voice, music, writing, etc, if you say you hate country music and then lump him in with the rest of it, if you cannot appreciate Johnny Cash even casually, then I do not want to talk to you, and I'm not sure I trust you as a human being.