The subject comes up a lot in questions here. Girls always say that they do like nice guys, but you still get guys saying that the girls are lying, or that guys are better off treating a girl like dirt. Why?!
I hate to break it to you guys, but you're not limited to either being nice or being a douche.
"Most girls end up with jerks because they started off as nice, decent guys and things changed."
Most girls end up with jerks because they started off as nice, decent guys and things changed. Some guys like that are also very good at preying on girls who think they can't do any better. No one deserves to be deceived or degraded in such a way, and I don't know why anyone would think a person could find that attractive. So, please stop encouraging guys to be douches, you're only furthering the widespread idea that men are pigs who can't be trusted.
If jerks are out, that leaves us with nice guys, right? Not exactly. Nice guys don't come in one variety; when it comes to relationships, I would say there are two types.
I'll start with the passive nice guy:
This is the nice guy that girls frequently pass up. He's always there for us when we need him, he's kind and treats us with respect, he might even try to help us with guy problems. What doesn't he do? Flirt with us, show us he's interested, or take advantage of an opportunity when we're single. He leaves the ball in our court at all times. He makes a great friend, but he'll always be just a friend unless he learns to take some initiative. Why? Because a guy like that will let you walk all over him, and that doesn't make for a healthy relationship.
The other type is the assertive nice guy:
He's as caring and respectful as the passive nice guy, but he doesn't help us with guy problems, he playfully says we should be with him. He makes sure we know he's interested before leaving the ball in our court. We don't have to worry about him treating us like dirt, or letting us walk all over him--we feel like his equal. While a guy who's a jerk might start off making us feel special, the assertive nice guy isn't just putting on an act for the time being. And unlike the passive nice guy, he can make us feel like we're important to him as more than just a friend. He's the ideal guy.
"The idea of experiencing new things with your significant other is appealing to most people, and "bad boys" offer that."
While I'm discussing nice guys vs. jerks, I'll touch upon the topic of "bad boys":
I don't consider them to be a separate type, and I don't think they're automatically grouped in with jerks either. Why do girls like these guys? Because they're bold and adventurous. The idea of experiencing new things with your significant other is appealing to most people, and "bad boys" offer that. But an assertive nice guy can easily be bold and adventurous, so don't assume that "bad" actually means the guy is corrupt or harmful to a girl the way a guy who shows no respect for her is.
I can't speak for all girls; this is simply my opinion. However, the next time a girl says she prefers nice guys, I highly suggest any non-believers take the aforementioned into consideration before calling her a liar.