I guess I'm what you'd call a party bug (it's like a party animal, but smaller). I'm not exactly painting the town every night, because I'm uncomfortable in crowds and use phrases like "painting the town" because I'm secretly 80, but I've been to my fair share of social events and town-painting hoedowns.
For a while I avoided big parties, because I'm a socially awkward person and because (and I know this is rare) I didn't actually start drinking until I turned 21, because I was a good little boy. When I did turn 21 and was thus societologically obligated to enter the party scene as its newest and hippest gadabout, I turned to movies to learn everything I needed to know about parties. I don't recommend this plan because, as with most things, movies lied about the big party.
You didn't hear about Scott's party? Oh my God, you have to go, everyone's going to be there, even and especially Scott. It's the freaking social event of the freaking year, you can't just stay home. Last year someone drank a lot and then did a wacky or embarrassing thing and everyone who wasn't there to see it is an asshole and has been effectively ostracized from society. Come to Scott's party, and also bring ice.
Movies need parties to be cathartic or life-changing. Superbad treats getting to a crappy house party like an epic quest during which our protagonists confront each other with huge secrets they'd been hiding all year. House Party has that big house party. All of the characters in Can't Hardly Wait use the party as the perfect time to make public declarations of love or wild, out-of-character life decisions. The party in American Pie is the holy grail for our protagonists, all of whom have vowed to lose their virginity at that party, because the best part of having sex is thinking "Hey, my buddy is doing this too, cool."
"I hope Steve's having as much fun as I am. I bet he's smiling. What a cool guy."