I really like this passage from a 2005 interview with Rene Spencer Saller, a friend of a friend:
People talk a lot about guilty pleasures -- what you like that you're not supposed to like. It's all such a lie, because I've never met anyone that doesn't love to divulge their guilty pleasures. "Oh, look at me, I'm so cool. Not only do I like Bjork, I'm also really into obscure bubblegum girl groups from the '60s!" They're proud of it because it distinguishes them from the other little consumers that are out there, loading these cool bands onto their iPods.