Greetings

 Usually, we, Japanese people exchange different greetings in accordance with time; morning, afternoon and night. Of course, the politeness depends on who we greet to.

 Also, it is uncommon for us to hug and kiss when they meet for the first time.
People seem to avoid even shaking hands.
It is said that old people in Japan were afraid that he or she might have weapons in his or her hands.

 Instead of shaking hands, we bow politely, which express gratitude, apologies and requests.
There are different ways of bowing depending on the situation.

 In my opinion, this is because to show the head, which is an important part of body means that 'I trust you'.
We sometimes bow even on the phone!