@sun a preschool teacher once announced this rule:
1. if you hit someone, you get in trouble
2. if someone hits you and you hit them back, ONLY YOU get in trouble.
I was, at that young age, already an asshole, and I knew a particular kid had no self-control, so I hit him and got him in trouble three times before I got tired of it.

Uncharitably, that kid was a moron who was unable to navigate a rule this simple, to retaliate through the teacher instead of directly.
Charitably, this kid stuck to his intuition and what his parents told him (correctly, that tit-for-tat keeps people from persistently abusing you) and simply refused to care about this malicious teacher's preschool punishments.

But my clearest lessons in how bad school is, were
1. home-schooling for a couple of years and in those years picking up lifelong habits that still support me, putting schooling's minimal contributions in perspective.
2. having a close sibling going through the same school system a few years behind me, and consulting notes to see how rapid the degeneration was. A program rewarded reading above grade-level for me, would a few years later punish that.