Each place has its own culture. Here are a few weird cultures in Germany students should know:
1. Wind from the window is poisonous
People in Germany have a habit of closing all windows in their homes because they think winds from the windows can make them sick. If you are a person who likes to chill in your room, you will feel a bit stifled by this. Therefore, in case you feel the urge to go out and enjoy the fresh air.
2. Do not celebrate early birthday party
Germans say that it is not good to celebrate an early birthday. They usually invite their friends to have a birthday party in the evening just before their birthday but at 12 noon they will receive their wishes.
3. "Please" means "yes" and "thanks" means "no"
An easy example, if the Germans ask you to drink more beer you do not say "danke" (thanks) they will understand what you mean by "no, thanks". Conversely, if you say "please", they will understand "yes, please". Please pay attention to this.
4. Answer directly on question
Germans love accuracy. If you only ask questions "yes" or "no" you will get the same answer. But if you want to ask for details, they will be ready just for you. For example, you specifically asked your way to a certain place.
5. Hang missing things on tree
Germans have a habit of not picking anyone's belongings when it's not yours. So in case you can find the lost you can hang up the tree. Often, people are missing items near railways or tram stations in Germany. If so, come to the tree near to find it again.
6. It is difficult to drink pure water
Germans never invited guests to drink purified water because, in their view, this was impolite. Because German definition about "purified water" means at least effervescent or in a bottle. So do not be surprised when you go to the restaurant you call purified water but what you get is a carbonated water.