How to Win Friends and Influence People by Dale Carnegieby Parker on TwosPRINCIPLE 2 - Show respect for the other person's opinions. Never say, "You're wrong."If you tell them they are wrong, do you make them want to agree with you? Never.You cannot teach a man anything; you can only help him to find it within himself.Showing respect for all customers’ opinions and treating them diplomatically and courteously will help beat the competition.You will never get into trouble by admitting that you may be wrong. That will stop all argument and inspire your opponent to be just as fair and open and broad-minded as you are. It will make him want to admit that he, too, may be wrong.