Criminal Minds, series 8, episode 10. "The Lesson." A clearly insane man is working on a macabre puppet show, and abducts a man and a woman to play the roles of Mitch and Steph, the puppets his father was famous for. He didn't know anything was wrong - he had Peter Pan Syndrome.
Criminal Minds, series 4, episode 20. "Conflicted." The killer, Adam Jackson, has MPD - he lures men in with his 'Amanda' personality, rapes and strangles them. He as Adam has no idea what he's doing.
"Insanity is doing the same thing over and over and expecting different results." -Albert Einstein.