In Bavaria, I paid for my drink, I asked her for "Ruckgeld", but only got the integer part of the money back, the rest of it, she kept it for tip! I looked her in the eye and she understood that I wasn't happy with that "initiative", but wouldn't blink an eye!
My company advised me to let it go, mentioning that if I was going to ask for the change, she would swear.
Notice how she didn't return me the correct amount back and then stare at me, demanding for tip, but she would decide for me!
Since, I will be around for a week or so, I was thinking of paying the exact amount of money next time. Will I get in an uncomfortable situation of having the waiter stare at me, demanding a tip? In other words, is tipping mandatory in Germany?
PS: Having experienced the tipping-cruelty in USA, and having tipped generously waiters across the Mediterranean for their supreme behavior, this Saturday night came as a shock, since I had the impression that this awful habit was only a USA-thing (you know, just like the fake audience laughing they have in USA TV series :) ).