"Criticism is futile because it puts a person on the defensive and usually makes him strive to justify himself." The person you blame doesn't hear your correction — he hears a threat, and "Any fool can criticize, condemn and complain — and most fools do." Carnegie argues that even convicted killers considered themselves justified, and "Criticism is dangerous, because it wounds a person's precious pride, hurts his sense of importance, and arouses resentment." The correction you wanted to deliver is now behind a wall of self-defense you built yourself. His prescription: "Instead of condemning people, let's try to understand them, and to figure out why they do what they do."

— In our words · Source: How to Win Friends and Influence People (Dale Carnegie)