Why do women like bad boy type of men and not sweet nice ones?

Am frustrated, am considered a super sweet nice guy. I love to please and be nice, I see women go for the bad, mean type. I don't want to change to something am not, I like being nice and myself. Is there any woman that likes the nice, sweet, attentive guy type. What attracts about the bad dude type, they guy with problems, instead of the clean nice sweet guy. What do I do, ladies please help me here?