Love him or loathe him, James Spader's kooky, pseudo-philosophical turn as Robert California is what kept the engine running on The Office after Steve Carrell's unfortunate exit from the show. Michael Scott was undoubtedly the lifeblood of the American adaptation, and without him, viewers were rightfully weary of tuning in to watch a show without its heart.
You can argue that the show should never have continued without Carrell. And, in fact, the last two seasons truly felt like a bizarro version of The Office, where the rules of the natural universe no longer applied to Scranton, Pennsylvania. There, "The Lizard King" Robert California thrived.
Spader was brought aboard via a lightning round of stunt casting that also included the likes of Jim Carrey, Ricky Gervais, and Ray Romano, all of whom played various weirdoes and doofuses interviewing for the branch manager vacancy left by Michael Scott.
Spader didn't feel like a natural fit for the show, which might have been his most appealing trait. After watching the writers struggle to shoehorn a "Michael Scott type" into the old position -- most cruelly with the shell of Andy Bernard -- it was refreshing to see someone so unlike anyone else in the show's grounded universe take the reigns for a bit.