In our society, and every society, there are rules. Ideally, all the rules are applied equally, and nobody feels put out by having to abide by them.
Some rules evolved naturally, as a consequence of some activity which people engaged in. That’s why in the US, and in many countries, we drive on the right. We decided, when we still were using horses and buggies, that keeping to the right – even when walking on the sidewalk – facilitated movement.