Four economists are taking a shower. One’s a classical, one’s a Keynesian, one’s a monetarist, and one is a Marxist.
The hot water goes out because someone started the dishwasher.
The classical economist stands there for 90 minutes, shivering in the cold water. He does that because he believes that the hot water will eventually come back on and there’s nothing he should do to bring it back sooner.
The Keynesian starts fiddling with both the hot and cold water valves in an attempt to fine-tune the system while using a government-issued emergency hot water supply he had installed in his shower. Unfortunately, the supply only delivers the hot water to certain sectors of the shower and most of it goes down the drain. Darn leakage!
The monetarist doesn’t want to shiver and he doesn’t want to waste water. He just turns off the cold water and enjoys the warmth of a slowly increasing trickle of warm water. This works well until 2008, when the pipes freeze and the velocity of the water goes almost to zero.
The Marxist thinks the other three are total idiots and lashes out by smashing the hot water tank, leaving everyone and everything equally dirty. Showering was an opiate of the masses.