In Vietnam, as well as in China and Japan, it is important to give and receive items with two hands. It is not enough to do so with the right hand – it must be both hands together. Using both hands at the same time suggests you are giving full dedication to the item or transaction at (and in!) hand.
In Asia, the exchange of business cards is particularly important – a kind of opening ritual. Not presenting your business card can be seen as a sign that you are withholding something or that your business is not completely genuine. Make sure you have cards printed before you go to Vietnam and that you have your card at the ready – held with both hands – as soon as you enter and are exchanging greetings.
In Europe, people are used to giving and receiving things with one hand and generally with whatever hand is available. However, the right hand is still the ‘best’ hand: it is the hand with which you shake hands in a greeting, as well as the hand with which you normally give a salute or wave to someone.
It is a funny thing that people in the West often pride themselves on being able to do things with only one hand or equally well with one hand as with the other – but they are never proud of being able to do something with two!