I think the concept of "rudeness" is underappreciated. (Or, if people are appreciating it, they're doing so quietly where I can't find out about it)
I think a lot of coordination-social-tech relies on there being some kind of social karmic balance. A lot of actions aren't expressly illegal, and not even blatantly all-the-time socially sanctioned. But if you do them a bit, it's considered rude, and if you're rude all the time, you get a reputation for being rude, and this comes with some consequences (i.e. not invited to as many parties).
The-concept-of-rudeness gives you a tool to softly shape your culture, and have some kind of standards, without having to be really rigid about it.
[Edited to add]
I'm writing this post because I was writing another coordination/epistemic-norms post, and I found myself wanting to write the sentence "If you do [X thing], it should be considered a bit rude. If you do [X' worse version of X thing], it's more rude." And then I realized this was resting on some underlying assumptions about coordination-culture that might not be obvious to everyone. (i.e. that it's good to have some things be considered "rude")
I come from a game-design background. In many games, there are multiple resources, and there are multiple game-mechanics for spending those resources, or having them interact with each other. You might have life-points, you might have some kind of "money" (which can store value and then be spent in arbitrary quantities), or renewable resources (like grains that grow back every year, and spoil if you leave them too long).
Many good games have rich mechanics that you can fine-tune, to shape the player's experience. A flexible mechanic gives you knobs-to-turn, to make some actions more expensive or cheaper.
The invention of "money" in real life was a useful coordination mechanic.
The invention of "vague social capital that you accumulate doing high status respectable things, and which you can lose by doing low status unrespectable things" predates money by a long time, and is still sometimes useful in ways that money is not.
A feeling-of-rudeness is one particular flavor of what "spending-down social capital" can feel like, from the inside of a social interaction.
Different cultures have different conceptions of "what is rude." Some of that is silly/meaningless, or actively harmful. Some of it is arbitrary (but maybe the arbitrariness is doing some secret social cohesion that's not obvious and autists should learn to respect anyway). In some cultures belching at a meal is rude, in others not belching at a meal is rude. I think there's probably value in having shared scripts for showing respect.
Epistemic cultures have their own uses for "the rudeness mechanic."
You might consider it rude to loudly assert people should agree with you, without putting forth evidence to support your claim.
You might consider it rude to make a strong claim without being willing to make concrete bets based on it. Or, you might consider it rude to demand people to make bets on topics that are fuzzy and aren't actually amenable to forecasting.
Rudeness depends on circumstance
Different domains might warrant different kinds of conceptions-of-rudeness. In the military, I suspect "being rude to your superiors" is actually an important thing to discourage, so that decisions can get made quickly. But it can be actively harmful in innovation driven industries.
An individual norm of "rudeness" can be context-dependent and depend on other norms. According to this Quora article, in Japan it's normally rude to tell your boss he's wrong, but also you're supposed to go out drinking with your boss where it's more okay to say rude things under the cover of alcohol.
Problems with Rudeness
There are costs/risks to the rudeness mechanic. The flexibility that it provides also lets you selectively punish people for unrelated social/political reasons. Cultures can acquire dumb norms, or norms that once made sense but are not maladaptive, and rudeness is one way for that dumbness to get implemented.
A problem with Cosmopolitan Melting Pot Cultures is that there's too many different forms of rudeness to keep track of, which someone can arbitrarily start trying to enforce on you, and I think people have developed a healthy aversion to unilateral rudeness enforcement.
But overall I'm a fan of it as a game mechanic. I think it's good for communities with barriers-to-entry to have their own cultures optimizing for particular things, and for rudeness to be one of their tools.