Politeness is very important for everyone. Everyone should know how to be polite and behave well to others because polite in one country may be impolite in another. For Example, when people meet, they often shake hands. In the United States people shake hands firmly for a few minute but in some the Middle Eastern countries, people hold the person's hand gently for a longer. Some countries making eye contact show respect but some countries are rude. About personal space when people talking, In North America people stand about an arm's length when they have conversation but some other countries stand closer can be awkward. The book name is Kiss, Bow or Shake Hands that wrote by three authors discuss about cultural difference such as greetings, gift-giving, and time. About "giving gifts", In United States, when you receive gift, you should open it while giver are with you. In China you should open a gift when giver is gone.
About "time" , If someone invite you to dinner. Some countries, you should arrive there on time, but some other countries you should arrive there after the time of the invitation around 30 to 60 minutes. About “gestures” , It is also different from one culture to another. In Thailand, It is rude to touch someone on the head with the hands and gesture for "come here" in the United States is used for calling animals.