All the guys I see who act like total assholes are the ones the chicks flock around. You know, the ones who have their hands all over every female in sight, and steal stuff from the girls, and otherwise act like complete and utter jackasses?
Ain't nothing wrong with having one's hands all over "every female" in sight, as long as it's welcome. Ain't nothing wrong with playing with 'em, either, as long as it's welcome.
I think that's the distinction you're failing to make. Some girls enjoy guys who can have fun and show attention to them. These also usually happen to be the cutest ladies, the ones that are accustomed to receiving the attention.
Tell me... when's the last time you tried to be nice to a classically "unattractive" girl? Try it sometime. You might be surprised.
All the girls won't hesitate to say how "nice" and "sweet" I am, but would they even think of going out with me? Nope.
It takes more than "nice" and "sweet" to equal "attractive". Girls also don't find men who are weak-willed, spineless, or snivelling to be attractive. Do you often complain about how no girl will ever fall in love with you? Do you often make snide remarks about a girl that goes out with Jimmy Quarterback? If so, here's a tip... that's a very unattractive trait.
Maybe you've just been unlucky and have only met girls that are absolute bitches. But y'know what? I'm betting that your own personality comes into play a tad, too.