If you have to go to the bathroom, do not ask where the bathroom is - you will only confuse the other person. Instead, ask where the toilet is (“Wo ist die Toilette?”).
Helpful hint: In most restaurants the bathroom is located downstairs or in the back.
For the most part, the gestures that are offensive in North America are offensive in Germany as well.
Germany is a much more formal society, and therefore last names with the titles “Herr” (Mr.) and “Frau” (Ms.) are used much more frequently than in North America. First names are normally reserved for family and close friends.
Eye contact in Germany is a sign that someone is acknowledging you and that they are paying attention. This is not an act of aggression, and so therefore should be returned. But don’t expect everyone to look and smile at you when walking down the street.
As a rule, when someone asks your name, you are being asked for your last name instead of your first. Germany is a more formal society, and the use of the last name does not indicate any lack of respect or attempt to be distant. Also, it is customary to shake hands with everyone when meeting as well as when departing.
The main difference between making and receiving calls between Germany and the U.S. is that Germans do not normally answer the phone by saying “Hello”. Instead, they offer their last name. Likewise, the caller is also expected to give their last name upon making a connection. When the phone call is finished, it is common to hear either "Tschüss” or “Auf Wiederhören” in place of “Good-bye”.