I recently spent a night at a hotel with an outdoor saltwater soaking pool. I didn’t see much of the hotel itself because I could not convince my body that there was even one good reason to leave the buoyant 102°F saltwater paradise. I braided my hair ahead of time with the—in hindsight ridiculous—idea that maybe I could keep it dry, but by the time I finally conceded I needed to go to bed, it was thoroughly wet. So I toweled it dry-ish, ran a brush through it, and fell into bed for a deep, restful sleep. I woke up ...