Not every win requires someone else's equal loss

In a true zero-sum game, like splitting a fixed pot of money, one side's gain is exactly the other side's loss. But most real negotiations — trade deals, pay raises tied to growth, a business partnership — aren't fixed pies at all; both sides can end up better off. Treating a positive-sum situation as zero-sum is one of the most common reasoning mistakes in economics and negotiation.

— John von Neumann and Oskar Morgenstern, Theory of Games and Economic Behavior — 1944