Whether you’ve just woken up or are about to go to bed, are sweaty from a run or need to warm up after a cold walk home, showers are a rejuvenating joy. They can also be a great place to think. According to a 2016 study by cognitive scientist Scott Barry Kaufman, 72 percent of people have their best ideas in the shower. If Reddit is anything to go by, they have weird ideas as well as good ones. The online forum’s “showerthoughts” community is home to 16.3 million people sharing their “miniature epiphanies.” Posts on the thread range from the existential: “You have existed since the beginning of the universe, but only realized it when you gained consciousness,” to the very silly: “The trees cut down to make Jenga blocks are repeatedly forced to relive their own death.�...