Having lived in two German-speaking countries, I recall often hearing about how superficial and shallow Americans were because we would greet each other with "How are you?"
Let me explain. Here in the USA, "How are you?" is a type of greeting that means roughly the same thing as "Hello, nice to see you" or even just "Hello." It's "Hi!" with a smile. On the other hand, what an American perceives as a grumpy person in Germany may likely be a German having a perfectly happy day.
Just thought I'd mention it. 😎