I am told that you regret not what you did but what you didn't do; and so that's why I do everything, so as not to have any regrets.
He [Aristotle] pointed out that people who had become initiates in the various mystery religions were not required to learn any facts 'but to experience certain emotions and to be put in a certain disposition. ' Hence his famous literary theory that tragedy effected a purification (katharsis) of the emotions of terror and pity that amounted to an experience of rebirth.