In most places around the world, a horizontal shake of the head means 'no'. But in Bulgaria and Sri Lanka it means 'yes'. To show you mean 'no' you must nod your head up and down. In Greece, people jerk the head back, at the same time closing the eyes and raising the eyebrows to indicate 'no'. The Japanese use a special gesture to show something they don't understand something or don't know the answer to a question.
Japanese children hook little fingers to show they intend to keep a promise.
Italian kids trace an invisible cross on their chests to show the same. In Korea and the Philippines, it's considered rude to beckon someone by moving the index finger back and forth. Instead the hand is held palm-down, and the fingers wiggled. The English word 'goodbye' is derived from the phrase 'God be with you'. A wave of the hand accompanies most goodbyes, at least in the West.