I was saying that you'd stake your house and life on Santa Claus (as the entity that delivers presents to every child in one night with his reindeer) not existing. Not even the smallest bit of doubt enters your head. You are absolutely 100% confident.

That's how many atheists feel about the god considered by most Christians. Short of some insane brainwashing, it's just not possible to force yourself to "believe" just in case it proves useful later.