What cultural faux pas should I try to avoid making in Berlin?

"It is important to be aware of the cultural norms in Berlin. It is considered rude to be late for appointments or social engagements, so it is important to be punctual. It is also important to be respectful of the local customs and traditions, such as taking off your shoes when entering someone's home. Additionally, it is important to be aware of the local language and to avoid speaking English in public unless it is necessary. Finally, it is important to be aware of the local dress code and to dress appropriately for the occasion," remarked another expat who made the move to Berlin, Germany.