Why do people rub chopsticks between their palms before using them, especially after the chopsticks have just been dettached from each other in fast-food oriental joints?
In Japan and China a guest / patron who "sands" chopsticks is considered impolite and insulting to the host/ chef.. The implication, the utensils are of poor quality.
In China the host rubs his chopsticks together, not the guests. Not certain of the meaning. This is probably the source of the confusion.