UBUNTU (not the distro).

Greet everyone, even a nod or a wave. An acknowledged individual is seen. Exists.

You don't Exist of they don't recognize your humanity (presence).

It's a big thing to greet people here on South Africa. You must.

People won't even listen to you or look straight through you if you do not acknowledge them.

We sometimes say "hello how are you" just as a thing before we even ask a question like "where's the bathroom".

I've even a greeted road construction workers while driving and they greet back. People on the street. In cars etc.

Try it sometime, just "see someone" and acknowledge they Exist in some way