You can tell people they are wrong by a look or an intonation or a gesture just as eloquently as you can in words - and if you tell then they are wrong, do you make them want to agree with you? Never! For you have struck a direct blow at their intelligence, judgment, pride and self-respect. That will make them want to strike back. But it will never make them want to change their minds. You may then hurl at them with the logic of Plato or Immanuel Kant, but you will not alter their opinions, for you have hurt their feelings.
Dale Carnegie in How to Win Friends & Influence People
