Rules nobody enforces are the ones that show who actually follows rules.

Most places run partly on rules nobody checks, and those rules work only because most people follow them when they could easily not. That makes them a quiet measurement. A rule with a penalty attached tells you who avoids penalties. A rule with nothing behind it tells you who actually agreed to be part of the thing.

Notice the ones you have been treating as optional because there is no consequence. You do not have to become rigid about it. Just pick the one you would be embarrassed to be caught breaking and stop breaking it.