You’re driving your old classic car with a partner on your way to work, through a hot, barren desert. The commute is ridiculously long; lately it has stretched to more than an hour each way, in part because the ancient car can go only 40 miles an hour. What’s worse, it lacks an air conditioner. You both roll down the windows, but that barely helps. By the time you get to work each day, you’re dripping with sweat. Your trip back home is even hotter. You could stand it if the breeze were stronger or the commute weren’t as long. “We need air conditioning,” your partner says. Here’s a classic illustration of the failure to think systematically.