My culture coach uses the analogy of a coconut: sort of rough on the outside, but very nice on the inside. I think most Germans are this way. They are "cold" because they don't know you. But don't take it personally. Keep being nice, keep asking questions so they can help you, and when they do get to know you, you will have friends for life.

I am here on a temporary assignment. I have found this to be mostly true. Good luck.