Nature is nothing if not parsimonious, especially when it comes to the human body. There’s a reason we don’t have webbed feet or nut-cracking beaks like other species, and that’s because we don’t need them. The system isn’t perfect, of course. If you ever wind up having painful abdominal surgery, odds are pretty fair that it will be your good-for-nothing appendix that’s to blame. And wisdom teeth seem a lot less wise when you consider how often they fall down on the job and need to get yanked.
As it turns out, the same why-bother pointlessness is true of what you might consider one of your loveliest features: your chin.