Haha well like any country that shares a language, our cultures are different. I don't feel too bad though, the German that's visiting the customer with me was also confused about how to order a plain black cup of coffee.
Sometimes it's hard to go to a different region in the US and understand exactly what's going. (Soda=Pop=Coke all mean the same thing depending on where you are in the states).
The "deep south" tends to have it's own dialect that are hard for anyone not from the south to understand sometimes.