I guess, "I wouldn't understand."
I do not get peoples' attitudes toward sleep. If you're going to get 8 hours of sleep, you can do it from 11 P. M. to 7 A. M. or you can do it from 3 A. M. to 11 A. M.
If you're hanging around or working in bars that open at 11 PM, then sure. If you play online games with friends on the west coast who go online at 11 P. M. eastern time, sure.
But if you're playing video games, watching TV (with TiVo), reading, or doing a million other things that people do, it might be nice to roughly match the working world.
I hear, "I just can't go to sleep at 11 P. M."
You can if you get up at 7 A. M. and keep busy until 11 P. M. A few days adjustment on the front end and the back end takes care of itself. Presto! Sleep cycle amended!
Another thing that seems barking mad to me is, "I just need another 15 minutes."
After sleeping for 7 hours, 15 more minutes--especially after rousing--is nothing. It may make you 10 minutes late. That's something. But 15 minutes more sleep matters only if you are catnapping.
So look around at the grown ups and get with the plan, you slackers!