In restaurants, if the service is satisfactory, it is customary to leave a tip which is l0 to l5 percent of the total amount of the bill. You may leave this in cash on the table before you leave or add it onto the bill if you charge it. As a rule, gifts are given only to relatives and close friends. It is acceptable to give a gift to a host or hostess or to someone with whom you have a more casual or friendly relationship, but it is not required or even very common to do so. It is acceptable to give teachers a gift to show your appreciation, but it is better to do so after you have completed the course.
Cards are more common to send and to receive.
Americans usually give gifts to family and friends at Christmas, birthdays, weddings, graduations and child-births. Gifts are also sometimes given to someone who has moved into a new house or is moving away. Greeting cards are given to acquaintances who are not close friends. Gifts are not expected to be very expensive. More expensive gifts are acceptable between people who are close to one another.