Cletus: here's my theory on the question you posited-- nice girls (at least the nice girls who are also widely considered attractive) almost never date nice guys because they can afford to be picky in whom they romance. So naturally they gravitate to men who (Duh!) are widely considered attractive by
females.
Now's where it gets tricky. (okay, not really) Since attractive men have much easier access to the cream of the femme crop, they tend to become arrogant assholes; the definition of "NOT nice". Let's be realistic here, how often is Fraternity Freddy or Star Quarterback a nice guy? Hell yes, I am sure some are Princes among Men, and kind to little old ladies, door-knocking Mormons and even Pauly Shore-- but the majority are those straight-teethed golden boys anyone sensible loves to hate.
So here you have your reason, devoid of any hypocritical pretenses, and touchy-feely BS. If you're pretty fugly like me, you can be nicer than Roy Rogers on Prozac and you still ain't gittin' no play.
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Please shower me with the righteous "you are a cynical prick" now. I feel guilty for my largesse of XP and love whining-hearts in full attack mode dimly countering the truth.