If discussions about a possible agreement are not business-like or unfocused, Germans will readily exercise their veto. Or, if they have an alternative approach, they will reject the initial proposal, thereby affecting a change of course and eliminating unnecessary discussion.
Germans tend to be well prepared before deciding on whether to enter into an agreement, and assume that the other parties are too. Usually, they have a plan or proposal ready. Instead of explaining point for point why they reject a given proposal, they simply respond with a no.
Because the no can come fast and definitively, it can throw the non-German party off balance. One needs to remain calm and describe clearly the reasons for one’s own proposal. If they are valid, the German partner will take them seriously and actively seek out the best approach, including a compromise.