Not because it's cool to be seen listening to.
I found this statement some days ago on this blog: Mainstream Isn't So Bad...Is It? and it is a wise device as I think. "A guilty pleasure is known as a something one considers pleasurable despite it being mainly received negatively or looked down on by a majority of society." A guilty pleasure is something you like, but you hide this affection, worrying about being uncool in the eyes of your environment. I looked at the guilty pleasure tag on Last.fm and found 87 of the top 100 songs in my iTunes. That makes me to the most uncool person here, doesn't it? Our friends, acquaintances, community, social life, whatsoever defines what a guilty pleasure is. Without doubt, everyone has some favorite songs that he/she listens, feeling inadequate, defining this to be a guilty pleasure makes it a bit more acceptable, doesn't it?