I know, I was there
A stupid thing to say that just makes the other person look even dumber, like they’re the one who just said something embarrassing.
'I know, I was there,' he said, after I told him he looked like a clown.
'I know, I was there,' he said, when I told him he failed the test.
'I know, I was there,' he said, even though he was the one who spilled the drink.