According to the passage,

Unconsciously, we all keep a comfortable distance around us when we interact with other people. This space between another person and us forms invisible walls. The amount of space changes depending on the nature of the relationship. For example, we are usually more comfortable standing close to family members than to strangers. Personality also determines the size of the area with which we are comfortable when talking to people. Introverts often prefer to interact with others at a greater distance than do extroverts. Cultural styles are important too. A Japanese employer and employee usually stand farther apart while talking than their American counterparts. Latin Americans and Arabs tend to stand closer than Americans do when talking. For Americans, the usual distance in social conversation ranges from about an arm’s length to four feet. Less space in the American culture may be associated with either greater intimacy or aggressive behavior. The common practice of saying "Excuse me" for the slightest accidental touching of another person reveals how uncomfortable Americans are if people are too close. In cultures where close physical contact is acceptable and even desirable, Americans may be perceived as cold and distant.