Not real: Nice guys are too nice. No one can always be that nice unless they're a saint. They are busy being nice instead of being real and women instinctively do not trust that. Bad boys "keep it real". Nice guys do not want to upset the apple cart.
Respect: No one respects a doormat. Nice guys do not set boundaries or make any real demands. A bad boy does not let a woman walk all over him or control him. Women can not respect a man they can control. No respect = No attraction.
Predictable: Most people lead cycling , predictable lives, so they're attracted to people who are exciting and unpredictable. Bad boys are always a challenge. Nice guys are never a challenge. Predictable = No excitement = No challenge = I prefer a bad boy.
Mother Nature: Women are designed to nurture. However, instead of doing this with children, they often end up doing it with bad boys. They think their love will save them. Nice guys rarely need to be saved.
Fixer-Upper: Nice guys do not usually need to be fixed. Bad boys usually do, so they become a project. Women think if they can "create" the perfect man, he will never leave them. Also, if they're busy fixing someone else, they do not have to look at what needs to be fixed in their own lives.
Sperm wars: Women are designed to procreate with the strongest possible genes. Bad boys are sending an unconscious message that they have great genes, so they're not afraid of losing the woman by misbehaving. Nice guys are sending a message that they do not think their genes are good enough, so they will not misbehave.
Fear of intimidation: If a woman is afraid of intimidation, she subconsciously knows she can avoid it with a bad boy, since she can never get close enough to him to have to go there. A nice guy will eventually want a commitment, and that's scary.
Low self-esteem: We do not feel comfortable with people who treat us better than we treat ourselves. If you do not think much of yourself, the bad boy is simply reinforcing your negative belief. A nice guy is treating you in a way you're unfamiliar with.
Sex: Women feel a nice guy will not be good in bed. They like to be manhandled sometimes and think a nice guy will not be able to take control and get the job done. A bad boy comes across as being able to get the job done, even though that may not always be the case.
Hot: Have you ever seen a bad boy who was not hot? I'm sure there are a few, but they would not be able to get away with half the stuff they did if they did not look so good. Meanwhile, when a woman describes someone as a nice guy, she means, "He's not hot".
Charm: Nice guys do not always know what to say, and are sometimes at a loss for words. Bad boys can be very charming and know exactly what women want to hear. However, they ever switch over to being selfish. By the time they reveal their true colors, the woman has fallen for them and has a hard time letting go.
Protection: Historically, men have protected women - physically and otherwise. Bad boys give the illusion of being able to protect women, while with nice guys, women are not so sure.
Life is about balance. Most men fall into either the bad boy or the nice guy category. The ideal man is neither, but walks that fine line between the two. Until men learn how to do this, more often than not, women will choose the bad boy.