So these are the really loud behaviours, and not necessarily what I was thinking of.

https://en.wikipedia.org/wiki/Civil_inattention

So there's a thing which I can't find the name of but it's something like a civil inattention sniff. It's a brief sniff at the moment someone walks past you. I'm not saying this one is cultural or geographical. It's possibly universal, I'm making a reference to the signal vs noise ratio.

If you've never noticed the civil inattention sniff, you may start noticing it now, or noticing yourself do it. I was decades on this earth before I picked up on it. It's a similar amount of signal to feeling the weather change in your knees.

A tiny signal in background noise of input of many physical senses.

I believe and suggest that it's true that there are many of these micro behaviours in many different regional cultures, but I'm not stating as fact or backing that up with science here. This is just an exploratory idea for me that I enjoy speculating on.