One thing to prepare yourself for is the slap of candor: Germans can be rather blunt when they offer stern advice or criticism. Frankness is seen as a virtue here, and the locals rarely go out of their way to enfold criticism in rhetorical bubble-wrap.
Advice and instructions can also be served up in a brusque manner. Some newcomers assume that they're being addressed in a stern or condescending way because they're foreigners, but this is generally not the case. Bluntness is simply widespread here.
Does this mean that the Germans are arrogant? Arrogance is to some extent in the eyes of the beholder (i.e. the person being sneered at), but yes, the Germans do display a streak of arrogance more often than many other peoples. When you can't bend very far, you have to stiffen yourself in ways that demand a tough and equally arrogant stance. This is one of the less endearing qualities discernible throughout larger parts of German society.
In some way, even the mere act of walking down a busy street or in the aisles of a crowded shop or exhibition hall can turn into an annoying experience for many newcomers .
Germans have two ways of dealing with strangers who share a crowded public space with them: they either ignore them entirely by staring straight ahead (with the occasional unintended bumping that this invites) or they stare at the others like there is something wrong with them. Again, these two forms of behavior are quite common here, so do not take it personally.
And then one last take on customs and etiquette here in Germany: you now should have an idea how to comport yourself with friends, people in your building and neighborhood shops as well as business associates. But most people you'll encounter here don't fit into any of the above categories. Still, there are rules on how you should handle strangers that will also make your adjustment to life in Germany easier . Most public transport maintains special seats for the elderly or infirm, which are designated as such. If you happen to have planted yourself in one of these seats (which is perfectly permissible when the vehicle is not crowded), do give up the seat without being asked to by the elderly or infirm (which should include obviously pregnant women). Sure, you'll see a lot of locals who ignore this rule, but you want to model yourself on decent behavior, not on the louts and lazy types.
And now something that may sound like strange advice: do not be overly friendly to strangers. As this is not a common practice here, some people may take you for unbalanced or think you're out to get something from them. With total strangers, it is best to stay on the safe, slightly cool side of courtesy.
Further, don't lean on strangers' cars or loiter in front of the residence of people you don't know. In the former case, the owners may become enraged as the car is a near sacred object in Germany, and in the latter case, people may think you're up to no good loitering in front of their homes.
And don't get upset if you are waiting for a friend or colleague who does live there and someone else from the building approaches you and asks what you're doing there. This is a standard measure of precaution taken by many people here. If asked, just smile and tell them whom you're waiting for.
When the warm weather settles in (thanks to global warming we should see more of it), you may notice as you stroll in parks, alongside rivers or small lakes that a number of people here engage in public nude sunbathing. This will undoubtedly be a shock for many coming from more reserved countries. But beware: it is considered rather offensive to ogle at the nude sunbathers. You can appreciate their commitment to the full-body bronze out of the far corner of your eye, but don't linger and never stare at these sun-lovers.
These are just some of the highlights of German customs and etiquette. It would be impossible to put into a few pages all the rules and nuances governing behavior here. And these days, the whole question is more open and fluid as certain groups here have their own rules of etiquette and comportment. Most university students, for example, study for at least one semester abroad, giving them a greater awareness for other cultures. And some younger adults and "Alternative Scene" types will, for instance, suggest during a first lively conversation that you switch to the familiar "Du" form.
If you make an honest, good-natured effort, most people here will readily forgive your early gaffes. Before long, doing the proper German thing will become almost second nature. In fact, it's not uncommon that when you go back home for a visit, old friends and relatives may remark how "German" you've become.
Also, it won't be long before you'll pick up some of the other, less important rules that we weren't able to cover here. Always keep in mind that German society is not held together by a series of hard-to-decipher and harder-to-follow rules. Most customs are out in the open and not that difficult to either grasp or emulate. Germans pride themselves on being guided by reason, and you, too, will probably agree that most of the new dos and taboos that you need to learn are all pretty reasonable.