I was thinking more of a sense of alienation that may exist rather than whether or not you actually knew the people. Our sense of the world and what is normal may be different.
I’ve noticed that people today can’t even be bothered to be polite or friendly even in situations where it is professionally wise to keep as many lines out there and open. There’s a sort of ‘leave me the hell alone’ quality to most people in passing.
When I was growing up, it became easier to show good manners than to endure corrections when I was rude or careless. In time it became automatic behavior.
I don't think that training is practiced much anymore.