"Tell me something I don't know".
A phrase often used sarcastically in conversations when someone says something obvious or that we are aware of. There is no surprise involved.
What if I said to you "Tell me something I already know", would I also be sarcastic?
Listening to what we already know gives us the chance to check our knowledge on the subject and see how close or how far we are to it.
Nothing is repetition if we always get something new out of the situation.
Just when you think you know something, it's important to see it from a different perspective.
What would you like to me tell you that you already know?