This could be based on an English saying 'Fool me once, shame on you. Fool me twice, shame on me.' It is saying that if you are tricked by someone once, then the trickster has reason to feel shame, but if you fall for the same trick twice, then you should be shamed for not learning the lesson from the first time.

I think this means that if someone has fooled you (made you believe something that wasn't true, made you look stupid, played a joke on you, etc.) then you'll learn from it, and no one will fool you with that joke again. But the "you" throws me off. I think it'd be "Fool me, you can't fool me again." or "Fool me, I can't get fooled again."

Not to be confused with The Who's song, WON'T GET FOOLED AGAIN *The Who=60's British rock band if you are scratching your head

Oh, I feel stupid. That's what she's saying...Yeah, that came to mind but I figured since she didn't ask it someone just said it, but not the saying. Hehe, Bush, Bush. Bush...

The correct saying I believe is: Fool me once, shame on you. Fool me twice, shame on me. (If the meaning isn't obvious, it means that the first time -- I didn't know. But the second time, I should know, and now it is my fault.) Bush messed up this saying and many others. If you want a great list you can check this out: http://www.slate.com/id/2208132/ 15. "It's important for us to explain to our nation that life is important. It's not only life of babies, but it's life of children living in, you know, the dark dungeons of the Internet."—Arlington Heights, Ill., Oct. 24, 2000