From Dale Carnegie’s How To Win Friends And Influence People, said to Benjamin Franklin.
Ben, you are impossible. Your opinions have a slap in them for everyone who differs with you. They have become so offensive that nobody cares for them. Your friends find they enjoy themselves better when you are not around. You know so much that no man can tell you anything. Indeed, no man is going to try, for the effort would lead only to discomfort and hard work. So you are not likely ever to know any more than you do now, which is very little.
Some less harsh advice:
When we are wrong, we may admit it to ourselves. And if we are handled gently and tactfully, we may admit it to others and even take pride in our frankness and broad-mindedness. But not if someone else is trying to ram the unpalatable fact down our esophagus.