German bureaucracy is equally confusing to many Germans as it is to foreigners. This is why most major services have open office hours with personal counselors. However, even one of these personal consultations can result in you accidentally setting up a road-block for yourself.
How could this happen? Usually because you asked for something that was not possible on their part, or at least perceived to be that way. You could be asking the impossible of them without even being aware of it, or you could be asking for something that apparently extends beyond their job description. The majority of German civil servants are really not that touchy, but not being able to get around one who is can be extremely difficult.
German civil servants tend to put the structure of their organization ahead of their own part. Their tasks were given to them for a reason, and it is not in the interest of the organization to let small issues spread to the attention of other departments if not necessary. After all, even the smallest component of a system is necessary to keep the whole from falling apart.
Giving information is always in the job description of these counselors, and they are happy to give it to anyone who takes consideration of their busy schedule by coming in advance. Coming well prepared is critical, also. In most cases they will take care of all of your needs to the fullest possible extent right there and then.