How to Say, Oh, You Don't Say

You don't say as a way of sort of ironically saying, yeah, that's obvious. So it's kind of like a way of stating that something is obvious in a kind of ironic, sarcastic way. You don't say funny because when you repeat an expression or a word over and over and over again, it just stops meaning anything. I've completely forgotten what the expression means. Because it'll help me, can anyone help me out, please? What does you don't say mean? I'm going to get together here. Just get my mind together here. Right. That pretty much wraps this up. Actually, I wonder if there's something I can find an interesting bit of