Whom do the diner workers consider the best customer?

Truck drivers are the best customers because is they stop to eat.... everyone stops to eat. Truck drivers always know the best diners.

Mae is the contact, smiling, irritated, near to outbreak; smiling while her eyes look on past—unless for truck drivers. There's the backbone of the joint. Where the trucks stop, that's where the customers come. Can't fool truck drivers, they know. They bring the customer. They know. Give 'em a stale cup a coffee an' they're off the joint. Treat 'em right an' they come back.