Many individual fallacies in economics are founded on the larger, and usually implicit, fallacious assumption that economic transactions are a zero-sum process, in which what is gained by someone is lost by someone else. But voluntary economic transactions – whether between employer and employee, tenant and landlord, or international trade – would not continue to take place unless both parties were better off making these transactions than not making them. Obvious as this may seem, its implications are not always obvious to those who advocate policies to help one party to these transactions.
-Prof. Thomas Sowell
(H/T: Cafe Hayek)