Re: officers are called 'sir'
What some people have said anything over and above being polite and offering assitance to a customer, should be initated by the customer. It should be upto the customer to initate small talk, that way they don't feel obliged to do so if a member of staff initates it.
Sure staff get to know the regular customers and what kind of interaction they like.
On the continent of wild endeavour in the mountains of solace and solitude there stood the citadel of the time lords, the oldest and most mighty race in the universe looking down on the galaxies below sworn never to interfere only to watch.