All-nighters. I never pulled one in high school, but I probably got too comfortable with them in my first year of college. I don't think I can count on both hands the number of nights I got absolutely no sleep and consequently hated myself the next day. This is an approximate account of what many of those nights and following mornings were like.
12:00 AM: till practically daytime for me. Probably was doing homework (or binge watching Netflix), but watching the clock as my usual bed time nears...
1:00 AM: Eh, should probably go to bed, but I mean, I'm used to going to sleep around 2, there's practically no point in trying right now because I won't even fall asleep. I could take melatonin, but like do I really need the extra hour? No.
2:00 AM: Agh, I remember when I went to bed at 11 in high school. Why do I do this to myself every day? Rock-a-bye Clara on the top bunk, you are so stupid, you really screwed up (for the 48th night in a row).
2:01 AM: *enter friends and company* How did you even get in here, there's a key swipe...
2:02 AM: Um pls go away, I am trying to get beauty rest.
Common alternatives to the above included: ordering Pizza X, banging my head in to my finite textbook and having dance parties in the lounge.
FYI: you'll more than likely find yourself pulling all-nighters or just losing out on sleep for what seems like no good reason (your friend will just sit on your floor, eating your food, and chatting the night away OR you're being a stellar friend and taking care of them after a very rough night). Even though at the time you'll probably want to just burrow under your covers and make them leave without being rude because you have an exam the next day, EMBRACE THESE NIGHTS. These are the ones that you'll fondly recall when the year comes to an end. Real talk, freshman year is one huge slumber party. It's freakin' awesome. But also remember that sleep is technically necessary for human survival.