I asked a woman from Leipzig "How is it going?" She replied that she was stressed. Maybe Germans respond differently, but it seems like a sign of respect. What do you think?

There is a big cultural difference: in Germany, we only ask that question when we really want to know how the other person is, and the other person will usually answer honestly. For us, it is a sign of closeness and genuine interest, not just a greeting, and waiters and cashiers in Germany would never ask you how you are. However, when somebody asks us how we are and we have told them, the normal thing here is to ask them how they are too. The lady from Leipzig was answering normally for a German, but being slightly rude by not asking how you were.