Aloof,

Mark Twain used to say something along the line that fools are actually not those who forget what they have learnt, but those who , after they commit the error and realize they have been thoroughly wrong, go around claiming that they knew all along that they shouldn't have done what they did. By doing that, according to him, they try to salvage their pride, even when it was all along obvious to others that their pride had been utterly misplaced.

Need I say more?