i don't know. I was never happy in school, all the typical depression stuff feeling trapped in a prison etc. In the last year I was counting days before it finally ends. school isn't a place where you have zero responsibility, you have to pass the tests, do homework etc. The only good part of school is the friends you make (provided you aren't constantly bullied, luckily I wasn't).

nostalgia warps ones perception of school. they forget about the mundane and stressful aspects and only remember the good times.