They behave like machines carrying an arrogance of Authority. Politeness is not a rule but exception and is seen when the other side too is carrying some authority (like money power, political power etc). They pretend to be attending to people but with scant regard for the human figure before them.
Your vote on this answer has already been received
Once I had been to the police station along with my neighbor to report chain snatching. The police told us to go through a few albums with photographs of suspects. It was late evening and the day shift police were in a hurry to go home and the night shift police were reporting to duty. And they were all changing their uniforms in front of us. So what ? My neighbor was a lady.