Totally get that familiar routine feeling, my coffee guy recognizes my usual order the second I walk in now. It makes the whole interaction feel less rushed and more personal somehow. Ever think about changing your order just to see what happens?
Guess it's more that he remembers your face and connects it to the shirt, not that the shirt itself tells him your order. Still, that's a cool little routine to have. Makes getting lunch feel less like a transaction. Do you ever worry about switching up your shirt and messing with the system?
Worrying about switching shirts is funny because I never do. My wardrobe is just five versions of the same thing. I'd probably confuse myself before the lunch guy.