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 them they are wrong, do you make them want to agree with you? Never! For you have struck a different blow at their intelligence, judgement, 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 all the logic of a Plato or an Immanuel Kant, but you will not alter their opinions, for you have hurt their feelings.
Never begin by announcing “I’m going to prove so-and-so to you.” That’s bad. That’s tantamount to saying: I’m smarter than you are. I’m going to tell you a thing or two and make you change your mind.
That is a challenge. It arouses opposition and makes the listener want to battle with you before you even start.
It is difficult, under even the most benign conditions, to change people’s minds. So why make it harder? Why handicap yourself?
If you are going to prove anything, don’t let anybody know it. Do it subtly, so adroitly, that no one will feel that you are doing it.
Courtesy: Dale Carnegie