suckiness
there's a somewhat popular t-shirt slogan: mean people suck. true, true. i think the converse is also true: sucky people are mean. it makes sense. if you're below average intelligence or ability, you suck. most sucky people can live with it for a while. but eventually that sense of knowing they're really not as good as everyone else just wears 'em down. turns 'em mean. so when someone's just plain being mean to you it might not be because you're doing something wrong. it might just be because they suck.