America is well-known for its equality, liberty, fraternity. Everyone is very friendly and informal. Children often call their parents by their first names and at work. Subordinates do not normally use "Mister" when addressing their supervisors. To those visitors who come from a more rigid and stratified society, such casualness can be confusing, leading to egregious（嚴(yán)重的）blunders. Conversely, many worldly, sophisticated Americans appear mortified because they feel America is not "civilized," with a capital "C." However, we know of terribly embarrassing incidents from mistakes which only an innocent foreigner would have made.
Public displays of affection between the sexes are very common, unlike perhaps where you have come from. In many cities, especially San Francisco, homosexuality is an accepted way of life. You may therefore see men being affectionate with men and women with women. If you disapprove of homosexuals because of your religious or cultural beliefs, please keep it to yourself. You might even find yourself a guest in a gay person's home-and might become shocked to realize that your host is a normal human being like any other and that you are actually enjoying his hospitality. Many couples also live together without being married-and may never marry. But you must realize their bond is probably as strong as the bond of marriage. So don't think one of them is available for a "date."
America is a notoriously "open" society, and to most foreigners Americans often appear exceptionally and "instantly" friendly. But sometimes such openness can lead to serious misunderstanding, especially between men and women. A casual invitation to have drinks and/or dinner does not mean that your American host also wants to become "intimate" with you afterwards. So be careful not to read too much into a friendly invitation.