And then one student said that happiness is what happens when you go to bed on the hottest night of the summer, a night so hot you can’t even wear a tee-shirt and you sleep on top of the sheets instead of under them, although try to sleep is probably more accurate. And then at some point late, late, late at night, say just a bit before dawn, the heat finally breaks and the night turns into cool and when you briefly wake up, you notice that you’re almost chilly, and in your groggy, half-consciousness, you reach over and pull the sheet around you and just that flimsy sheet makes it warm enough and you drift back off into a deep sleep. And it’s that reaching, that gesture, that reflex we have to pull what’s warm - whether it’s something or someone - toward us, that feeling we get when we do that, that feeling of being sad in the world and ready for sleep, that’s happiness.

— Paul Schmidtberger, Design Flaws of the Human Condition