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 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 all the logic of a Plato or an Immanuel Kant, but you will not alter their opinions, for you have hurt their feelings.
(November 24, 1888 – November 1, 1955) was an American writer and lecturer and the developer of famous courses in self-improvement, salesmanship, corporate training, public speaking and interpersonal skills. Born in poverty on a farm in Missouri, he was the author of How to Win Friends and Influence People, first published in 1936, a massive bestseller that remains popular today. He also wrote a biography of Abraham Lincoln, entitled Lincoln the Unknown, as well as several other books.