What NOT to Do with Chopsticks
Do not rub chopsticks together to remove splinters or wooden strings.
Do not tap chopsticks together in the air for practice or on a bowl to make noises.
Do not leave chopsticks standing in a bowl vertically.
Do not hold chopsticks in your hand with all five fingers as you would a weapon.
Do not use chopsticks to gesture while talking or to point at people or dishes. A common newbie mistake is to use chopsticks to point at a particular dish you are recommending. Even worse, never use your chopsticks to gesticulate or point at food while grunting with your mouth full!
Do not pass food to people with your chopsticks -- doing so resembles the practice of passing cremated bones at funerals. Instead, put the piece of food you intend to share directly onto the other person's plate.
Do not suck sauce off the ends of your chopsticks or nibble on the ends.