I don't think there's anything wrong with being pretentious actually. Many contemporary artists are however quite obscure to me and the level of self reference that some works contain flies over the head of someone like me with little interest and knowledge of where contemporary art is at the moment. Sure I get annoyed sometimes and can comment on some works with sarcasm but if I'm going to be honest, and not trying to be funny, I really wouldn't put myself over someone in that manner until I have at least tried understanding what they are about. The disrespect the likes of Damien Hirst, Tracy Emmin (as Mike mentions) receive is perhaps the thing that can make me do that plunge and make an honest attempt, read some books or whatever.
Until now my view has been that good art to me evokes a feeling in me (apart from annoyance that is...) or perhaps heighten my understanding of something and yes, some contemporary art I see does. It's just that when it's very little about skill anymore and all about concept the idea has to be very good and you have to share some kind of frame of reference with the artist.
This is a video an acquaintance did, she's an artist (not entirely safe for work):
She got a lot of scorn for it as people some people thought that this persona was truly her. I do think the irony and message is pretty clear and I think it's brilliant and hilarious (I don't know if it's clear for everyone though). The line between art and comedy for me is rather fuzzy though. I think perhaps that she goes in with it so committed makes it more art then comedy?
David Shrigley is a "contemporary" artist I do like maybe, again, because he makes me laugh?
This one for example.