Tarof is the Persian etiquette of deference, wherein one must both yield to others (you first!) and decline the offer (no, you!). One may not insist or accept until the end of the line--at least in this hilarious parody by Simon Garshasebi--so what happens when a circle forms?
There are similar norms of recursive politeness in Britain; perhaps that's why there are so many roundabouts there.
