Most people shake hands and make eye contact when they meet people for the first time. Among very good friends, a woman may give another woman a little hug, and a man may kiss a woman quickly on the cheek. Males don't hug one another, which, however, is changing. Men usually shake hands with the right hand. Sometimes they use the left hand to either cover the handshake or lightly hold the other person's arm. This shows greater warmth and friendship. Most people wave hello or good-bye by extending the palm(手掌) facing outward, and twisting the hand at the wrist. Another way is to raise the arm, palm outward, and move the whole arm and hand back and forth. This is important to know because in many other countries, the same movements mean "no".
When people are waiting in a public place, such as the post office, they usually form lines. Some people get angry and complain if someone pushes their way into a line or jumps ahead of other people. Moreover, many women like men to open doors for them. They also like men to give up their seats on public transportation. However, some women do not like this type of behavior. They feel that men and women should be treated in the same way.
In the United States, it's important to make direct eye contact in business and social situations. If you don't make eye contact, people will probably think that you are bored or not interested. If there is silence in these situations, people usually try to make conversation. Periods of silence make many people uncomfortable. People in the United States usually stand about one arm's length away from each other while talking or standing together. This space is called "the comfort zone".
In the United States, mothers sometimes show that they are angry with children by shaking an index finger(食指) at them. People may show that they like children by patting them on the head.