If you catch a dragonfly and bend the end of its body up, it will eat itself until it dies. When people have had their mouths numbed for dentistry, they must be warned not to chew their tongues. I think if we assume that pain is simply an evil we’re oversimplifying things.
“There is between sleep and us something like a pact, a treaty with no secret clauses, and according to this convention it is agreed that, far from being a dangerous, bewitching force, sleep will become domesticated and serve as an instrument of our power to act. We surrender to sleep, but in the way that the master entrusts himself to the slave who serves him.”
Maurice Blanchot