A lot of them aren't from what I've heard, but they really should care more. They need to think about who is buying their music and merchandise. I know my favorite band is known to be really nice in person and they like to hang out with their fans. In one interview their security guard for the tour said they were the nicest band he'd toured with in 20 years. I don't care how good or popular an artist is, without their fans they're nothing. Dissing the fans has cost many performers a lot of money and sometimes their careers, and rightfully so. I'm in a band, and I'd never disrespect someone at one of our shows. I'm not really famous (just slightly famous), but even if I was I'd remember who made me that way and thank them. Without a fan base, an artist is playing to an empty room. And guess what they're album sales are going to look like really quickly once that starts happening. I don't think a musician has any obligation at a concert other that to play his or her music. Anything else is an added bonus, or possibly an unfortunate detriment to the experience depending on the artist. That said, there are certain requirements that i believe artists meet. They should turn up on time, and they should play for a decent length of time. Other than that, I think an artist can act how he or she feels. There is no law