IT Coordinator at www.diem25.org, author of language courses (print and digital). Former head organizer of the Polyglot Gathering (largest international conference for language geeks).
I love learning & teaching languages, discussing politics and philosophy, and developing computer programs that process languages.
If you want to ask me something about languages, please check out Overview of my Language-Learning Advice or A2A me if there is a question I haven't yet written about, this is preferable to asking in private because more people will benefit from the answer.
Bringing flowers when visiting someone.
As long as the flowers are a colourful bouquet (or even a pretty potted plant) and not just roses, this won't necessarily be interpreted as a romantic gesture. Bring flowers when visiting elderly people in particular; parent-age people may also find a bottle of good wine or a box of expensive chocolates acceptable. Never come empty-handed. If going to a student party, you might bring something very cheap like a salty snack or a bottle of soda, but never come empty-handed.
Flowers are traditionally given to women. If visiting a work colleague at his home, you'd give the flowers to his wife (the lady of the house). I believe this is because traditionally the wife had to do the work of preparing for a guest.
Flowers are also often gifted by superiors as a form of recognition, for example for a woman's work anniversary, for women volunteers at an event, for female talk show guests or for female passer-bys on Mother's Day.
Apologizing for being late
In Germany, punctuality is seen very strictly: people generally expect an apology even if you're just two minutes late. And this happens quite often because not all Germans are good at being punctual.
Asking for the window or door to be shut
German windows are a wonder of technology: they can be opened partially (as in the photo) as well as completely (sideways). However, if you even partially open the window and there is another open window/door somewhere, some Germans will start to complain about the draft of air coming through. Sitting in the draft is believed to cause colds, so people are quick to request the window to be shut.
Lecturing people at the red light
If you're a pedestrian trying to cross the street on a red light, no matter if there are no cars in sight, be prepared to be lectured (and sometimes physically restrained) by any elderly German lady or parent with kids.
Separating trash
Since environmentalism is big in Germany, it's important to separate different kinds of trash so that they may be recycled. In a typical household you'll find trash cans for paper, recyclable packaging, organic waste and "other", while glass (separated into white/green/brown glass) is collected in big containers you can find nearby. Most glass bottles now have Pfand, meaning that you initially pay an extra fee which you will get back when/if you return the bottle to the store.
Respecting Authority
Kurt Tucholsky (German thinker) said it best: "The German nightmare is to stand in front of a counter, the German dream is to sit behind a counter."
Germans have a lot of respect for authorities:
1) those given power (bureaucrats, policemen) and
2) those who have authoritative knowledge of their field (teachers, doctors, lawyers)
Politicians on the other hand are given no respect; any American lawyer joke is a politician joke in Germany.
Talking about the news
It is assumed that everyone has been watching the news (or are too ashamed to admit if they haven't), so the news are a safe topic to discuss with anyone, including strangers on the street. They're kind of like the weather. There is little chance of offending anyone or getting into a heated argument because the consensus is that all German politicians are shitty and we're all just voting for the least bad choice. "Wahl zwischen Pest und Cholera" - a choice between falling prey to either pestilence or cholera is how we say it in German.
