While this would've been handy two years ago, I wouldn't say "auf wiedersehen" to say goodbye in Germany. That's the formal farewell that isn't used often. Tschüss (pronounced like "choose") is what you'd say of the time.
Divergent Travelers Travel Guide, With Tips And Hints To Germany. This is your ultimate travel cheat sheet to the Germany. Click to see our full Germany Travel Guide from the Divergent Travelers Adventure Travel Blog and also read about all of the different adventures you can have in Germany at http://www.divergenttravelers.com/destinations/germany/