Everywhere I look, people and gadgets are yelling at me to hydrate. On social media, the algorithm bombards me with fitness and beauty influencers who say I should drink a gallon of water a day. (Glowing skin! Shed that last stubborn five pounds! More energy!) The various smartwatches I test all have these hydration widgets for tracking my daily water intake. Not too long ago, I had a “smart” water bottle that flashed hourly rainbow LED lights as a reminder to drink up. Most recently,…