That'd be great, except...
... people are human. We're not Vulcans.
If you build organisations, processes or laws assuming rational actors with perfect information and ignore how human minds actually work, with all our biases, fears and emotions (and the variations thereof), you're going to have a bad time.
Consider that it may be optimal (for example) for there to be a social norm around not flashing your bum at people, because most people would feel that was unpleasant. Do you still insist we're not all better off if you keep your bum to yourself? No man is an island, as the saying goes. You want to live in the world, there are trade-offs. Some sacrifice is necessary. Trust is massive boon to efficiency, and it flows from courtesy, respect and an adherence to certain behavioural norms. You don't care about trust? Enjoy your moated castle. Anarchy is ideologically pure, but miserable in practice.