3rd

i think that bowing is japanese unique custom.
when we meet a person who we know, we cannot help bowing.
maybe japanese are shy, so people just bow to people without saying anything.
it is a useful way to show politeness.
if we want to thank someone, we sometimes just bow.
if we want to express that i am sorry, or ask to excuse me, we can do that just bowing.
some foreign people say that japanese bow too much, though.

on the contrary, i often see foreign people huggng each other.
when they take pictures, we can see those scenes often.
this behavior may be not easily acceprable for japanese at first.
foreign people like touching each other more than japanese.

these days, people have more and more communication with people in other countries so that diffent culture are mixing up.
i think japanese people will be used to see these different culture.
but i don't think bowing is a strange behavior for now.