A Fox entered the house of an actor and, rummaging through all his properties, came upon a Mask, an admirable imitation of a human head. He placed his paws on it and said, "What a beautiful head! Yet it is of no value, as it entirely lacks brains."
AesopIf you are wise you won't be deceived by the innocent airs of those whom you have once found to be dangerous.
Aesop