Joe Navarro said this quote

If you currently travel abroad or plan to in the future, make sure you understand the cultural convention of the country that you are visiting. Particularly with regard to greetings. If someone gives you a weak hand-shake, don't grimace. If anyone takes your arm, don't wince. If you are in the Middle East and a person wants to hold your hand, hold it. If you are a man visiting Russia, don't be surprised when your male host kisses your cheek, rather than hand. All of these greetings are as natural as way to express genuine sentiments as an American handshake. I am honored when an Arab or Asian man offers to take my hand because I know that it is a sign of high respect and trust. Accepting these cultural differences is the first step to better understanding and embracing diversity.

~ Joe Navarro

For instance, when people press their lips together in a manner that seems to make them disappear, it is a clear and common sign that they are troubled and something is wrong.

~ Joe Navarro