Why do neighborhoods have their own invisible rules?

The short answer

Each [derb](https://slowmorocco.com/glossary#derb) is a self-governing unit with codes that predate municipal law. The families share responsibility for cleaning, lighting, maintenance, and surveillance of the shared passage.

The rules are enforced socially. A family that doesn't sweep hears about it from the neighbour's look. Noise, unfamiliar faces, inappropriate behaviour — all regulated by the fact that everyone can see everyone else.

One derb is tidy, quiet, flowers on the wall. The next is louder, less maintained. The difference isn't wealth — it's social cohesion.