Why Do Nice Guys Finish Last?

We've all heard that nice guys finish last, but why does that have to be the case? What is it about nice guys that stops them getting the girl they want? Why do so many women take advantage of nice guys, and then leave them for some other jerk. Nice guy syndrome isn't about men being too nice, it's about men trying to be nice in order to get women to like them, which turns women off and prevents them from being attracted and wanting to become a girlfriend.