Alright, I'll admit it:
I have an addiction...
Just about every night, I get ready for bed about midnight. However, I don't usually get to bed til about 1. Why? I'll be listening to music, and I'll just want to hear one more song. Then another. Then another. I just can't stop. And the next thing I know, I've blown an hour playing solitaire whilst singing along to my favorite songs.
Besides the sleep I lose, though, I'm not so sure that this addiction is such a bad thing.