Sleep deprivation, as every dark site practitioner of “enhanced interrogation” knows, is the ultimate torture. Deprive the most well-trained partisan torture resister in the world of sleep for long enough and you will eventually break them in half, even as you render them insane. Being unable to sleep night after night, for whatever reason, will rob you of optimism and eventually destroy you.

On the other hand, a good night’s sleep is the best medicine. When you wake up after enough sleep your day starts off better, your mood is lighter. Get enough sleep day after day and your faith in the goodness of life and a large range of possibilities returns.

Of course, all bets are off when it comes to psychopaths. They may be insomniacs or machines that sleep exactly eight hours a night. What’s the difference?