It may be ignorance, or arrogance- but do something to overcome the brutal image we Americans have since Bush came to power, will ya?
Find the local rhythm.
Amercians have a hard time adjusting to the pace of life that isn't thier own, and as a rsult, they sometimes are labelled as "rude" and "pushy". In Germany dinner can take three hours or more, It's an experience. You can offend the waitstaff by trying to speed up the process.
Keep the Pauper attitude in mind: "I'm joyful to eat a meal in this marvelous land!"