@Tcof
You can just be a kid, all carefree without a care in the world
Yeah asian countries are notorious for their work process, but I hardly can call HS time carefree without care in the world. Especially in Japan where they have to study like crazy and than prepare for college\university exams. But I've heard that students of average Japanese colleges and universities have much easier time than highschoolers in terms of study process and free time. So basically entrance and final exams\job hunting are the the most difficult parts of college life. So in-between they could have like 2-3 years of pretty good life, better than high-school where you have to study non-stop. Very often students go to their local colleges so they don't need to rent flats\rooms, besides a lot of families have enough income to let them rent the room for their children without difficulties. But college\university setting is not that popular in manga\anime due to target audience.
if you find friends the new school then it is good. But honestly it still never really the same.
High-school it's just a 3 years, or rather 2,5, but you meet new people throughout life, not only in HS. Some of them become you friends (and i mean real friends not just some acquaintances), sometime you drift apart over time or circumstances, but HS has very little to do with it. HS, Japanese of not is not some magic place where special people eagerly waiting for friendship to come. It's just another obligatory social institution (boring af) where bunch of people spend a lot of time and sometimes make connections, just like colleges and workplaces. And I'd say childhood\teen friendship is the most unstable and fickle out of all friendships. Yeah, about this, just remember another popular manga trope "Whaaa! we'll end up in different classes next year, so we'll stop being friends". So much for "sparkling highschool friendship". Well, it's a bit sad, but after all it's not that big of a deal, that is not even real friends, just good classmates.
@Kamui
Yeah, I understand where this trope about idealized HS memories comes from (despite most of Japanese irl don't like their HS years at all, just like the rest of the world). But I find the very idea of such average activity with people who you can hardly even call "friends" presented as a "good memories" ridiculous. There is absolute nothing to remember. You'll forget about something like this in few years let alone 10-20 or so.
Edit:
Oh boy, it turned into wall of text. Just ignore my mumbling