A yes in the German context is more exception than the rule. Germans are reluctant to enter into an agreement without being sure that they can deliver on it. They respond almost instinctively with reasons why they cannot (yet) enter into an agreement.
The German no is more the rule than the exception. However, its level of hardness is based on contextual factors. It can range from a hard to a flexible no. Only through asking what the barriers are to the yes is it possible to discern how hard the German no actually is.
Because the German yes involves a high degree of commitment, before granting it Germans request a lot of context information. The term is front-loading.
In Germany follow-up is infrequent. Once an agreement has been made neither party feels the need to contact the other in order to inquire about the status or priority of that agreement. Agreed is agreed.
The Germans prefer a complete deliverable, even if late, over an incomplete deliverable, on time or even early. Lateness is tolerated as long as expectations are met. Completeness is preferred to speed.
Back to Germany.