When you leave high school and get out on your own, even if you're not completely independent, your eyes are sufficiently opened. You go about life in a completely different way, noticing all of the frivolous things you did when you were in high school pretending to understand the world. There are a lot of things that you just really don't need like:
A lot of friends. In high school we all feel like having a lot of friends is the key to being secure in ourselves but honestly, life is better with a tight group of great people. You want to be known, you want to be liked, but trust me that changes literally nothing about how you feel about yourself — that's all on you. When it comes to the people you associate with regularly, share your secrets with, party with, quality is so much more important than quantity.
To fight every single battle. The world is so mean, I get that, and there are constantly going to be people rubbing you the wrong way and saying things that are evil and blasphemous, but you can't fight all of them. You learn that some people are too stupid to absorb what you're trying to communicate so you just don't waste your breath. But don't let the world walk all over you either, just be smart about who you post up to in the comment section on Facebook, because not all debates are worth your time.
To fit in. If you go about life squeezing yourself into every trend, fad, and friend group, you're really going to lose sight of who you are. When you're in high school, fitting in, belonging, is so important, and then you graduate and realize how inconsequential those people you were trying to please actually are. Be yourself, wear what you want, listen to your favorite band even if they are scary or indie or awful. At the end of the day the more you do you the better you get at it and the more you love it.
TV. You get busy, you have better things to do and then your priorities change and you only tune in on Sundays to watch Game of Thrones. You set your DVR to record your favorite shows and then you go back when you can to binge watch "Shark Tank" and "Pretty Little Liars." I never know what's on TV anymore, I recently found out that half the shows that I used to watch got canceled so that's a bummer.
To always be doing something. I used to feel so much FOMO (Fear of Missing Out) when I was home on a Friday night but now I have learned to feel content with my lazy nights in. You will still see people having a great night at the club on their snapchat but you are binge-watching "Orange is The New Black" and you don't care about what the prom queen is doing with her weekend.
Have money to have fun. When you're broke you find ways to enjoy yourself and eat with six dollars in your bank account. You get pretty good at having fun without money and you realize that money and fun aren't synonymous. Granted money makes fun easier and more obtainable but it isn't necessary. Fun is free sometimes.
Get used to things changing. The quicker you accept the world as it changes the easier it is to live in.