Sleep doesn’t work like a health bar in a video game.

Different stages of sleep have different efficiencies. For instance, passing out drunk doesn’t count as sleep. You body is still active in digestion which can prevent a good sleep, or intoxication can prevent the brain from going into deep sleep.

Sleeping is an activity. Humans are just weird for closing both eyes and both sides of the brain at the same time, but it doesn’t mean that we shut down completely. Most animals do not sleep this way If we could experience partial sleeping like animals, we’d probably understand better what a good sleep is…