Today, I was talking with a coworker about a person from whom I was having trouble getting information.

We were talking French and I used a very common expression. I said "It's like pulling worms from his nose." (C'est comme lui tirer les vers du nez. Well actually, I was talking Québécois so I said, "ouin, c'est comme y tirer é vers du nez." )

Now, every French Québecer knows this means you have a hard time getting information from somebody, but if you look at the sentence there is absolutely no way you could guess its meaning.

Do you know of any other expressions like this?