Nocturnal bottleneck
I'm an absolutely incurable night owl. My theory is it must be an inherited trait, which is passed through the generations at random, and was first developed for a reason. For thousands of years, maybe longer, my forebears protected the rest of the tribe at night so everyone else could sleep peacefully and then go hunting or farming during the day. We were probably the ones that domesticated the wolf, I'd bet, as that makes sense. They'd be the ones coming around the campfires at night. And we'd say, hey buddy, want this juicy elk bone?In return for saving civilization, we're now persecuted by people who think 8 a.m. is a good time to start school.