ONLY ONE OF THE FOUR WAYS TO SPEND MONEY IS ACTUALLY EFFICIENT. Milton Friedman explained why in a single interview clip that's outlasted entire economics departments.Box one: your money, on yourself. You watch the cost and the quality, because you're the one paying and the one using it — this is the only box where both instincts fire at once.Box two: your money, on someone else. You still watch the cost, since it's coming out of your pocket, but the quality matters less to you, because you won'