If you are sitting at a table with people you don't know, it is impolite to smoke without first asking if it will disturb them. At American restaurants and coffee shops, cold water is usually served before you order. You may find the bread and the butter are free, and if you order coffee, you may get a free refill.
    Most cities and towns have no rules about opening and closing time for stores and restaurants, though they usually do make rules for bars. Especially in big cities, stores may be open 24 hours a day. Serving in restaurants are often large. If you can't finish the meal but would like to enjoy the food later, ask the waiter or the waitress for a “doggie bag”(剩菜袋). It may have a picture of a dog on it, but everybody knows you are taking the food for yourself. Tips are not usually added to check. You should leave a tip of about 15% on the table when you leave. In some restaurants, a waiter or waitress often brings your check on a plate, and you can put your money there. Then the waiter or the waitress brings you your changes.