Our personal identity is framed by the community we live in. Part of the way we see ourselves is in relation to other people, as belonging to this or that group. Your personal identity becomes somewhat threatened when your familiar community is replaced by foreign landscapes, people and lifestyles.
People respond with varying degrees of anxiety and confusion.
This is what is referred to as Culture Shock. In your home community people interact according to quite precise social rules. When you meet a new person you make eye contact, smile and shake their right hand. If you blow your nose you'll use a tissue or handkerchief. These acceptable ways of behaving have been taught to you since infancy.