I've heard about my quick post that said that it is judgmental to think someone is judgmental.  Ah -- this is a self-referential maxim on the general maxim to not be judgmental, and self-referential pronouncements often lead to trouble.

Obviously we must make judgments, about everything, as we as we skip through life, picking safe stones to step on and keeping out of the cold water.  We think, oh that stone looks slippery and that one is not stable, and so on.

This illustrates the difference between judging and being judgmental.  I judge the stones, but not on a moral basis, but just on how well they suit the purpose.

Seeking revenge, striving to enhance personal honor, hating, having a grudge, are all extreme manifestations of being judgmental.  It involves assigning value judgments ("good" and "bad") to behavior and people and things (of course we know things cannot be good or bad, so when we do this we are personifying them unrealistically).

Christians have the Biblical command to not be judgmental, that judgment belongs to God.  This would imply that such views of someone (that they are lazy, or dishonest, or whatever) should not be held and that doing so is something of a sin.  The reason given though is not very good.  Because God is the final judge doesn't mean we shouldn't make our personal decisions about people.

No I don't think there is much evil about being judgmental.  What is wrong with it is that it is unhealthy.  It makes us unhappy and disappointed and so on.  It has little effect on the person we are judging.