This theory has been confirmed first-hand by a former roommate of mine, in a discussion involving, of course, beer, and the Just Friends Syndrome.

Guy roommate 1: *bitches at some length about how he can't get women, 'cause he's too much of a nice guy*

Girl roommate: "Oh, I'm sure you'll get together with some really awesome girl sometime. The nice guy thing really isn't all that much. Of course, my boyfriend was originally an asshole, which drew me to him like a moth to a flame."

Even more amusing over the course of the year was the seriously unresolved sexual tension between those two. I was just glad I could sit back and watch without getting involved.