Okay, let's leave the average genre fiction off (no standard romance, standard scifi/fantasy, standard horror). What are the books you like most, but have to admit you couldn't tell anyone else that they'd actually enjoy. Not bad to laugh at (entirely), but embarrassingly fun-bad.

When your friends see you reading it, or see it on your shelf, what do you have to explain, defend, or deny?

What books do you avoid buying because, no matter how much you want them, you dread explaining them to your friends and visitors even more?