Once upon a time Kruger Dunning dug himself out of the grave. Though a zombie, he did not know that he was a zombie; to himself he looked normal, not a decaying horror; to him it was everyone else who looked like monsters.
To himself he moved at a normal speed, but with a persistent stumble. All the others, though zombies to him, moved super-fast. He wondered out loud how the zombie apocalypse got everyone except him.
Kruger Dunning never figured out why the ‘zombies’ – i.e. real humans – were smarter and quicker and stronger than him; nor why he was plagued by heat, cold, injuries and insects. Eventually a pack of dogs sniffed at him, and he decided to lie down and take a nap.
Moral: The incompetent cannot recognize their own incompetence.