Making generalizations about any society is difficult, but if you are a newcomer in Germany you will likely notice many small and seemingly large cultural differences. An honest and sincere effort to familiarize yourself with Germany's "dos and taboos" will help you integrate more quickly.
You are well advised to familiarize yourself with some of the basic customs and etiquette in Germany. You may very well find some aspect of German behavior rubs you the wrong way, but remember the whole society is not going to change just to accommodate you…no matter how sweet and personable you may be. So make an honest and good-natured effort, and it will help to make your stay more enjoyable.
The legacy of their painful history has made the Germans a somewhat cautious people. They are preoccupied with security, sometimes to the point of obsession in the eyes of some outsiders. But with a history that has seen so many disruptions, collapses and calamities, you can see why the people here crave a little security.
One result of this need for security is a certain reserve in relationships. Clearly, Germans are not as gushing or forthcoming as many other nationalities. For this reason, many consider the Germans to be cold or unfriendly. But it's really more a reflection of their wanting to be cautious before proceeding further in relationships. Once you've actually become friends with Germans, you'll discover they can be very good and very loyal friends indeed.
And a good way to gain and keep friends here is to learn the customs and etiquette that guide daily life. Arising from such factors as that deeply scarred history, the geography and population density, Germany has developed a tight network of customs and rules of conduct that may seem alternately quaint, strange, inspired or unreasonable to people coming from other cultures. But adopting (if only partially) these rules and customs quickly will make your stay here so much more pleasant. Besides, they're not really that demanding.
A large portion of the German rules of etiquette are easily ascertainable and close to universal. Some of it just involves good old common sense. German thoroughness comes into play in this area as well: you'll find that Germans say "Thank you" (Danke) and "Please" (Bitte) quite a bit. A lot of this very obvious politeness is, of course, formulaic and perfunctory. But if you offer your thanks and pleases with a bit of feeling, you'll often find you get a smile with the reply. These customs and rules of etiquette are...well, if not unique to Germany, at least nothing like universal. Some will be fairly easy to adopt, others may take a little getting used to before you're comfortable. None of them are so infinitely subtle (as in some cultures) that you have to be constantly hyper-alert so as not to offend others.
Let us start with the area of personal relationships: those close relationships can take some time to develop. In fact, many Germans – especially those who are older and more traditional – always keep those outside of a tight circle at arm's length. For that reason, you'll find that many people here will always address acquaintances or colleagues as "Frau Müller," "Herr Schmidt" – even people they've known for years, often folks with whom they've shared the same residential building for many years.
Speaking of addressing people, one key point of etiquette here is wishing everyone in your building or in your office "Guten Morgen/ Guten Tag/ Guten Abend (Good Morning/ Afternoon/ and Evening) and then adding their family names if you happen to know them.
You should also use those greetings (without the names generally) when entering small shops and businesses but not, of course, at supermarkets or department stores. Not to do so is seen as being a tad impolite and will probably influence the kind of service you get. These basic greetings are also still accepted behavior when getting into an elevator where you work, and then you should add a "Wiedersehen" when you or someone else steps out of the elevator.