I'll let you ponder over that one - You say this when you're too proud to admit you're an idiot,

You say this when you're too proud to admit you're an idiot, so you make up a story that makes it look like you're a genius.

'I'll let you ponder over that one' after I said my goldfish was writing a novel.

'I'll let you ponder over that one' when I told my friend I could read minds with my feet.

'I'll let you ponder over that one' after I told my teacher I was a scientist from the future.