W. Austin Gardner
Garbage Trucks

“Garbage trucks take their loads of trash to a place that accepts garbage. And people with problems take their gripes, gossip, and grumbling to someone who’ll accept it. Because you allow people to dump on you and make no effort to stop them, they keep dumping. And they won’t stop until you let them know they’re not welcome.”
Studies have shown that, in the average home, for every positive statement, a child receives 10 negative statements. The school environment is only slightly better; students hear seven negative statements from their teachers for every one positive statement. No wonder so many children are growing up feeling that they are losers. Parents and teachers are conveying that perception every day in how they talk to their children. These studies go on to point out that it takes four positive statements to negate the effect of one negative statement.
John C. Maxwell, Winning with People: Discover the People Principles That Work for You Every Time (Nashville, TN: HarperCollins Leadership, 2007).