My only business, as an at-seat coffee shop footslave, is to study the backs of my customers' socks - the socks of whoever chooses to sit above me at the coffee table.
It is none of my business who my customer is seated with, or what they are saying to their interlocutor, or even what type of coffee they are drinking. I must be solely focussed on the customer's socks!
Here you see me solely focussed on the backs of the socks of a middle-aged Indian lady.