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. Some husbands and wives avoid each other for that very reason and their marriages are disintegrating as a result. They have developed the habit of criticizing the way each other looks or talks, and the things each other does or does not do. As a result, the husband may stay late at work, then flee to the yard or workshop for refuge when he returns home.