I care about shoes. Controlling the meeting's focus is critical. When I passed the shoeshine stand, I was focused on getting to my gate. The salesperson broke my preoccupation with catching a plane and forced me to focus on my shoes. When you control the focus, you control the situation.
Eye contact is an important trust-building tool.
You convey confidence with eye contact. Looking customers in the eye and smiling with your eyes and mouth both help build trust and reduce a customer's reluctance to doing business with you. Helping customers discover their needs is part of the process. By getting me to look at my own shoes, I discovered that it had been a while between shoeshines. People rarely resist their own data and discoveries.