Nathan Fielder allows ordinary people to prepare for life's biggest moments by "rehearsing" them in carefully crafted simulations. Nathan Fielder allows ordinary people to prepare for life's biggest moments by "rehearsing" them in carefully crafted simulations. Nathan Fielder allows ordinary people to prepare for life's biggest moments by "rehearsing" them in carefully crafted simulations. Nathan Fielder allows ordinary people to prepare for life's biggest moments by "rehearsing" them in carefully crafted simulations.