LOL. Well I agree with your first three sentences, but I'd also add that we systematically the costs of false beliefs because (1) at the point of deception we cannot reliably predict future instances in which the self-deceptive belief will become a premise in a decision (2) in instances where we make a instrumentally poor decision due to a self-deception, we often receive diminished or no feedback (we are unaware of the dead stones floating down the river).