It is a Superstition In Germany, that if you Brake a Plate, it is considered good luck.
Es Zieht
German Homes are usually airtight, so opening your door to allow airflow to prevent mold growth actually makes sense.
Gift Giving
Knock on Wood
It is a superstition that Evil entities cannot touch Oak therefore before sitting down with a group, you knock on the table to prove you're not the devil or an evil entity.
lighting cigeret with a candle
It is a Superstition in Germany that each time someone Lights a cigarette with a candle, a sailor dies.