When we do it we play God. A fourth reason criticism is so foolish is that it tears down rather than builds up. When aimed at us, it seldom makes us want to change for the better, but rather, it has the opposite effect. It causes us to defend ourselves, to justify our actions, to try to prove that we are not as bad as we are accused of being. That sabotages our spiritual growth.
Criticism also leads to discouragement and self-pity.
We feel sorry for ourselves because we think we will never be able to please our critic and because we have to suffer this unjust accusation from him. We seldom grow while we are sulking. Criticism also tears down relationships. It alienates people and builds walls between them. I find criticism unpleasant, so my tendency is to avoid the people who level it.