A part of that might be the nostalgia from my own school days as a child and teen, of course ~ But overall so do I just think that the setting of a school always brings with it a good amount of scenarios and opportunities with all that it has to come with.
Like how you have certain divides/ groupings of the people you can find there like juniors & seniors, teachers & students , the rich kids and poor/ "poor" kids and so on and so forth ~ With their of course being additional groupings you can think of like the nerds, the sporty ones, the popular kids, the outsiders & etcetera ~

Then there's the whole thing about how the entire place are filled with those who are there to grow through out their education, but at the same time also grow as people socially and simply through the act of getting older. Going about that place with emotions running high and trying to figure out their lives. Turning the place into one heck of a messy space to be in for hours, days and weeks ~

When you take such a place like that and write anything from your down to earth realistic tale to your fantastical, supernatural, sci-fi and/or thriller horror story so can you get so much out of it. Especially if you really lean into all the different aspects that a school setting has to offer and take advantage of all that it has to give! Not that writing a scaled down story in such a setting is anything wrong either ~ :3
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TLDR; Setting a story in a school environment can be great! :D
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Thanks for reading what you read ~ <3
Hope you have a good day!