You can't win an argument. You can't because if you lose it, you lose it; and if you win it, you lose it. Why? Well, suppose you triumph over the other man and shoot his argument full of holes and prove that he is non compos mentis. Then what? You will feel fine. But what about him? You have made him feel inferior. You have hurt his pride. He will resent your triumph. And - A man convinced against his will Is of the same opinion still.

Dale Carnegie, How to Win Friends & Influence People