I might be wrong, but what if I am right? 也许是我错了, 但万一我对的话, 该怎么办? You're reading too much into it. 你的假设太离谱. You've got it all wrong. 你完全误解了.
You're all wet. 你全然误会了. It's all a big mistake. 这是个天大的误会. You're missing the whole point. 你没掌握住我话里的重点.
You've missed the point. 你误会了我的意思.