3 ideas
A small community keeps order through ten unwritten commandments that all reduce to one prohibition: 'You are not to think you are anything special.' Variants forbid believing you are as good, smart, or important as others, or that you can teach them anything. Their function is to punish any display of self-regard, so that ambition and distinction become social offenses.
The Jante code has no formal enforcer. Neighbors, schoolmates, and family keep watch on one another, and each person is both a victim of the rules and one of their enforcers. An added threat, 'Do you think we don't know anything about you?', shows that the code runs on shame and the fear of being exposed, not on law.
The book argues that a childhood of systematic belittling does not produce humility. It produces stored resentment, fear, and envy that the person carries away from the town inside himself. The humiliated person's sense of self stays both fragile and inflated, so rivalry and perceived slights can erupt into destruction. On this view, the murderer is partly manufactured by the community that forbade him to value himself.