h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Nice guys are sensitive guys. Early on in life they got picked on by the jerks, so they know firsthand why it's wrong to be a jerk. They don't want to be jerks, because they want people to like them (because they don't like being picked on), and they know that people will only like them if they're not jerks. But to be surprised that nice guys are also horny is just plain dumb. Being nice and wanting sex are not two mutually exclusive things. After all, humans have a biological imperative to reproduce, and nice guys, clearly, are human. And the fact that a nice guy might want to get in your pants doesn't mean that he is being nice for the PURPOSE of getting into your pants. Believe it or not, but there are plenty of nice guys who enjoy good conversation, and candlelight, and snuggling up on a rainy day. And there are also plenty of nice guys who like to open up and be honest. And there are even some guys who fall so deeply in love with a woman that they'll take a bullet for her.

There are also guys who are absolute jerks, who think that the secret of happiness lies in manipulating other people, and these guys can learn pretty easily how to act like a nice guy to get what they want. But it's easy to tell when you're dealing with one of these guys; he doesn't stick around.

If what you're saying is that nice guys have human urges, there is no argument. If what you're saying is that nice guys are really trying to be manipulative, you're dead wrong.