I usually hate to be pessimistic, but no1 may actually be on to something. In fact, you may have inadvertently agreed with him in your response to me, heh.
Remember that girl who gave you the "evil" eye? Wasn't she closely walking with another person - presumably a friend? If she was so mean, then why would she have a friend?
It actually brings up a really great question. Why DO mean people still have friends? I can only think of one answer. It's because "mean" people have no problem communicating their desires and needs. They may anger some people, but they can just as easily create new friendships when they're willing. They're not bound by the constraints of shame and displeasure. You could say they're evil, but you could also call them very shrewd and unattached.
Social phobes, on the other hand, possess the antithesis of this behavior. They ARE bound by intense amounts of shame. More importantly, they are bound to a system of justice. If they don't feel like something is just, they try to fix it by implicitly alerting everyone about the breech in conduct. If that doesn't work, they call for help. And if that doesn't work, then they lose all hope in themselves and humanity, and shut-down. If the world lacks "justice", then they don't want to be apart of it (because of the high chance of getting hurt).
In summary, the mean person may piss off a lot of people, but their avenues of communication are still open for an eventual relationship. Also, the people who may hate them still respect them for leaving that line of communication open. It shows a level of openness and honesty, which is generally liked in social species. The social phobe, on the other, shuts down all lines of communication and denies himself the ability to create new friendships. He may be wronged, but to the outside, he looks cold and unapproachable.
It's a cruel turn-of-events (i.e. everything happens the exact opposite of what you'd think), but it's frustratingly logical.