When I was in elementary school, my best friend never changed his socks. In fact, he simply never removed them from his feet, something his mother pointed out to me in an apparent effort to shame him into giving them up when I was at their house for a sleep over. "You wash your socks, don't you." She insisted on washing them that day, and once in her hands, she banged them on the table to show me that they were hard as boards.