As I munched my Monte, I reflected upon the semiotics of the archetypal sandwich, that is, the Platonic vision of Sandwich. Though the sandwich is historically the result of culinary theorizing by the leisure class (e.g., the Earl of), the traditional sandwich signifies the working man's lunch, something you eat with your hands during the busy workday.
I respect the homes of my friends. I would never think to smoke in their space, put feet on furniture, or sleep with their spouses (unless explicitly requested to do so). However, when I'm asked to take off my shoes, the message I receive is that the host feels their property (rugs, floors, etc., which presumably might be damaged by my shoes) or their sense of propriety or ritual (which apparently involves the perverse ceremony of disrobing my toes at the door) takes precedence over the comfort of their guests; i.e., me.