YOU SAID:
I am sad so you are sad.
INTO JAPANESE
悲しいので、あなたは悲しいです。
BACK INTO ENGLISH
You are sad because you are sad.
INTO JAPANESE
あなたは悲しいのであなたは悲しいです。
BACK INTO ENGLISH
You are sad because you are sad.
That didn't even make that much sense in English.