Mind your shoes and feet
After Iraqi journalist Muntadhar al-Zaidi's threw his shoes at President Bush, the commander-in-chief said he wasn't insulted. He should have been. In Arab countries, the soles of the feet are considered impure; flinging a shoe is no better than throwing offal. Buddha, too, taught that the feet are the lowest part of the body—physically and spiritually. Therefore, in most of Asia, showing the bottoms of one's feet, even accidentally pointing a foot at someone, is a grave insult.
Don't use your left hand
In the Middle East, South Asia and even parts of Africa, the left hand is reserved for sanitary practices. One must never touch food with it (or goods in the market, or strangers). In India, the tradition crosses into religious practice. During Hindu prayers, the prasad—or, gift—is received only with the right hand. For Muslims, too, right-handed eating is more than a simple matter of cleanliness. According to the Koran, "Satan eats and drinks with his left hand."
Always toast with eye contact
Just as a handshake is said to have originated as proof that your companion wasn't concealing a weapon, so goes the rumored origins of toasting by robustly clinking mugs. If a would-be assassin has poisoned a drink, he will be reluctant to see his drink mixed with his target's. Some cultures have gone even further. Drinkers in many European countries must prove their sincerity by looking into every other drinker's eyes during the toast. At a large table of friends, the process can take awhile, but failure invites a dire consequence: seven years of bad sex.
Never insult the royal family
Just ask any foreigner who's been to a movie theater in Thailand: The royal family is held in high regard. Before a film begins, patrons are asked to pay their respect to the king while a short reel about his life is shown. Failure to do so can result in criminal charges under "lèse majesté," or injury to the royals. As Harry Nicolaides found out, the law is often at odds with Western expectations of free speech. In 2008, Nicolaides was sentenced to three years in Thai jail for criticizing the monarchy in a book. He was eventually pardoned—after spending six months in prison.
Silence your nose
While China is renowned for its public expectoration, just across the sea South Koreans are more mindful of their phlegm and spittle. Even the slightest sniffle at the dinner table will paint you as a barbarian. This can be a tough trick for foreigners whose palates may not be ready for the omnipresent spicy gochujang sauce. Still, when you feel a sniffle approaching, excuse yourself and head to the bathroom. In Japan, using a handkerchief in public is also considered rude.
Manage your chopsticks
There's more to expert chopstick usage than simply getting food from plate to mouth. Chopsticks aren't meant to push bowls or plates around. Rarely are they used to pierce food, and morsels should never be passed directly between two sets of chopsticks. The most crucial misstep foreigners can make is improper placement. Chopsticks should never be placed vertically; say, in a bowl of rice. The two sticks will resemble incense used to honor the dead, and you will have invited death to the dinner table.
Go ahead, hold his hand
Even the most open-minded visitors to Middle Eastern and Arab countries are surprised by the close physical contact between men. "Arab men may be seen walking hand in hand," says Alinda Lewris, founder and executive director of the International Association of Protocol Consultants and Officers. "It is considered a sign of kinship and does not imply any sexual connotation." So, when your new Arab friend clutches your hand on the way to afternoon tea, give him a squeeze back. He's just being friendly.
Be quietly grateful
It runs counterintuitive to Western upbringing, where "please" and "thank you" are often the first pleasantries we learn as children. But thanking your Arab and South Asian hosts may lead to awkward moments. Thanking your host too much suggests they've done more than what was expected, that they deserve kindness. For them, being a generous host is standard practice. It's a useful lesson to learn. As one expat living in Goa says, "I have felt far more integrated since I dropped all the 'please's and 'thank you's, and [I] certainly attract far less curious looks."
Don't touch heads
The top of the body, too, carries its own importance in many parts of the world. In countries where Buddhism flourished, even generations ago—and those of Southeast Asia in particular—the head is said to contain one's soul. Noted travel journalist Everett Potter found out the hard way when he "patted someone on the head in Thailand, and realized with horror as I did it that I was committing a real faux pas." The head is sacred; don't touch it.
Don't shake hands across a threshold
In Mediterranean countries, even strangers kiss one other on the cheek; in Japan, bows are exchanged. In Russia, there's just one rule to remember: Never shake hands across a threshold. Says Matt Taibbi, Rolling Stone contributing editor and longtime Moscow resident, "Shaking hands 'cherez porok' is a major no-no. When I went to college there and tried to introduce myself to my teacher, she flipped out."