It is the custom that a man can stand very close to a friend who is a man,and a woman can stand very close to a woman. They can hold hands,or even put their arms around each other.However, if you do this to foreigners, they will probably feel unhappy. They will try to move away from you,or may ask you not to touch them, Remember,this doesn't mean they aren't friendly.It is because when you do that,you are inside their personal space,and they feel uncomfortable.