The North American gestures for OK will be interpreted very differently in Europe, South America and the Middle East.
We are now living in a global village. Citizens of many countries are travelling more than ever before, and experiencing different cultures and ways of life. However, verbal communication is still a barrier between many people. A modest command of a foreign language will go a long way but for those people who are linguistically handicapped and have very little or no knowledge of European, Asian or Latin American tongues use non verbal gestures to communicate more effectively. It is wise to know the ones that are polite and which ones will offend your hosts.
The most widely recognized American sign for OK is shown in two ways. There's the thumbs up sign, and making a circle with the index finger and thumb. In Arab societies the thumbs up sign would be extremely offensive and is best avoided. In northern Greece and the southern part of Sardinia it isn't well received either. Keep this is mind if trying to hitchhike along Sardinian or Greek roads, if the driver stops it is likely that he/she would give you a thump on the head instead of a ride.
The OK gesture used with the forefinger and thumb to make a circle has several meanings in many countries. In Brazil and Germany it is very rude, and would be like giving somebody the middle finger in North America. In Japan, after purchasing something you would be telling the sales clerk that you would like your change in coins. In France the meaning is negative but not insulting, it simply means "zero" or "worthless."
When making the V sign with the index and middle finger be careful how the hand is positioned. If the palm is turned inward the gesture won't be appreciated in Britain. One possible reason for this is that during the battle of Agincourt on October 25, 1415 British archers who were captured by their French adversaries had those fingers severed, so they couldn't utilize their bows and arrows. The men who survived the battle with no injuries flashed these fingers to the French, as a way of cursing them in a nonverbal manner.
Conveying yes or no can be puzzling for visitors to Bulgaria, Greece, Turkey and Iran. No is an upward and downward shaking of the head, and yes is side to side. When somebody says no in these countries they might also click their tongue. In Asia, saying no directly to a request is unheard of (especially in business situations). Instead, the response might be "We will have to look into that" or "I will try." Nobody can deny that smiling is the best way to diffuse a difficult situation in North America, but in Asia (especially China, Japan and Southeast Asia) it can be used to mask embarrassment, shyness, or anger.
When passing objects in the Middle East and parts of Asia, do not use the left hand. It will be considered impolite. When receiving something from another person it is customary to do so with both hands, especially when exchanging business cards in countries like Japan. In this case, do not place the card inside your pocket, but read it carefully and prop it against something on the desk for the duration of the meeting.
If you are unclear about shaking hands when meeting or leaving, follow the lead of your host. In some countries close friends may embrace each other or indulge in some shoulder or back slapping, this might cause embarrassment in some places and it might be best to just nod your head and smile.