Booth's Mental health

[Eva Elisabeth]

Thanks, Susan. Wow, I'm sorry, I didn't know that one. We would say that he knows his "Sache", which could be translated by "thing", "business", "matter" or "case". The German word for "stuff" is a very disrespectful, downgrading, risqué expression (for "Sache/n", thus all these words). Slang, and inapproproate in the very context in public domain.