I just found myself saying "Good morning!" to people with the honest impression that it was morning and not 3PM & the end of the school day. Ugh.
So, when I was a freshman in college, there were these really cool, party-type trumpet players who were seniors or fifth-year seniors. I hung out with them a bit, when I wasn't hanging with my homeys from The Quad. One day, after dinner (around 7PM), I was hanging out with them and listening to some Mahler symphonies, when one of them woke up and came out of the bedroom of the apartment. He looked like absolute dreck - bed head to the extreme, bloodshot eyes, etc. He cracked open a beer (he was 21) and sat down in front of the TV. "Man, I've got a lit paper due in a couple of hours. Stupid 2nd period classes."
His roommate threw a couch pillow at him from across the room. "You idiot. It's 7PM. You overslept by about twelve hours."
The guy said, "Really?", looked at his watch, put his beer down and went back to bed.
Ahhh... the good life. When it was possible to oversleep, and when the only things to worry about were lit papers and practicing the horn.