- The boredom of being imprisoned all day long
- The slavery of feeling forced to do uninteresting homework
- Lack of free time after school to pursue your own interests or learn your own material
- The toxic culture in school, and being forced to be around people you hate all day long.
- Lack of sleep, etc...
...all to regurgitate a bunch of short-term memory into a piece of paper, and forget it soon afterwards.
For most honest people, school was mostly boring and overall a waste of time.