I KNOW THAT'S RIGHT
When you're so sure about what someone is saying, you might as well be the one who thought of it first.
'You said that? I know that's right!' he said, like he was the one who came up with the idea.
'I know that's right!' she said, even though she didn't get the point.
He said, 'I know that's right!' like he was the king of the whole conversation.