In Knights of the Old Republic, HK-47 is supposed to be a consummate and perfect assassin, but he acts more like a psychotic thug and cannot keep himself from slipping threats and sinister implications into his dialogue all the time.
Predator and Predator 2 provide a perfect example, as the consummate trophy hunter/Proud Warrior Race Guy alien stalks and kills dozens of dangerous, deadly men, only for one of his would-be victims to Take a Level in Badass and begin to hunt him in exactly the same fashion.
Neatly subverted in an episode of Perfect Strangers in which Larry claimed to be immune to hypnosis, proceeds to go under with consummate ease — then reveals about a minute later that he's only pretending, and he actually can't be hypnotised.