Being weirdly formal (who the fuck calls their dad sir???) There's a bit in Debt: The First 5,000 Years where Graeber describes how most of our etiquette is essentially the petit bourgeoisie affecting the social relations of feudal lords, pretending that our baseline, non-exchange obligations to each other, down to our pleasantries, are still somehow an exchange. Definitely something that you still find more entrenched in the US than anywhere else.

Having the audacity to openly ask someone how much they earn in order to know if you need to care about them as a human being instead of having the human fucking decency of trying to infer it from their clothing, body and speech patterns like a civilised human On the other hand, there's the culture of not asking your coworkers what they make, which is a tactic to discourage organizing. Maybe a better rule would be to not ask random people what they make unless it's to build class consciousness or to organize your coworkers. I'm not sure.