It's also a meme, of which you may not be aware. It comes from Ralph Wiggum, the caricature of the special needs child on The Simpsons, when he says, "Me fail E

It's also a meme, of which you may not be aware. It comes from Ralph Wiggum, the caricature of the special needs child on The Simpsons, when he says, "Me fail English? That's unpossible!" In common use, it's generally taken to mean exactly what the GP poster intended: a mock expression of surprise at a thing that is, in fact, assumed to be the case.