The definition of politeness is behaving in a way that is respectful and considerate of others.  Unfortunately determining what is respectful and considerate is subjective and there is the rub.

Considerate behaviour should align with expectations.  Individual expectations can vary considerable and group expectations are formed from cultural bias.

What?

In English the expression what can be associated with body language indicating incredibility.  That is, the observered behaviour is considered outlandish or outside the norm.  

Such an expression, used about some action that is a  behaviour norm in another culture will fall flat.  Perception and expectation drive the interpretation of politeness.

Picking up the Garbage

In North America there are public garbage receptacles everywhere.  Still there is garbage randomly cast aside everwhere, just check your local park.

In Japan there are virtually no public garbage receptacles and despite this there is virtually no garbage in public places.  

In Japan, it is considered impolite to dispose of your garbage anywhere but home and the main deviation from this is the by foriegn tourists. 

The cultural norm of the country very much drives behaviour.  Of course that is not to say there are some impolite people but their occurance is rare.

Practicing Logic

While individual expectations and cultural bias is a reality the benefit of polite behaviour is the pleasure it brings to others, and so to yourself.

Understanding the context of behaviour norms  is valuable but most important is self awareness about the impacts of your beviour on others.

In the moment reacting to and meeting their needs and expectations can and should be more of an exercise in applied logic than guessing what the expectations are.