When you're in high school, everything feels momentous and important. Then, the second you walk out of those gates for good, all of it - every single event, team, fight, hookup, embarrassment - completely ceases to matter for the rest of your life. This is beginning to be very common knowledge among adults, but it's hard to grasp when you're there for yourself because, as mentioned, it feels like you are in the middle of the most important time of your life. And you are, but not in the way you think at the time.
It feels like this relationship will go on forever and will matter to you with the burning intensity of a thousand suns for the rest of eternity. Then three months later you're at university and nothing could be further from your mind than your childish hookups. You get a "C" instead of a "B" in your class, which drags down your entire GPA and it is SO IMPORTANT, until it just isn't. Or she says he says she says you did and EVERYONE KNOWS and OH MY GOD IT IS THE END OF THE WORLD but then it isn't. Because the most important thing that happens in high school is that you develop a personality. You wait until the hormonal fire in your brain settles down to a gentle three-alarm blaze and if you actually overcame obstacles, you'll be a decent human being. If, on the other hand, high school felt so easy that it was like barrelling down an oiled waterslide giving high-fives on both sides and crashing into a pool of non-stop bikini chocolate-wrestling, real life is going to kick you in the guts straight away when you graduate.
You can climb the social ladder in high school all you like. When you get out, though, the world tips that ladder upside down, shakes you all off and says that, if you don't like it, you'd better fight back. The only people who succeed and never outgrow high school are politicians, and I'm not sure "politics" really counts as "success".
Mokalus of Borg
PS - My own high school journey is kind of a blur in my memory.
PPS - Mostly I think it was frustrating.