Easily one of the best shows I've watched recently. I'm a sucker for a psychological thriller and this show absolutely delivered.
I loved the concept of "severance" as a whole - the idea of your "innie" only living during work hours is truly horrifying, as is the lack of autonomy the "innie" experiences by essentially being forced to continue indefinitely until the "outie" decides to retire.
The entire cast was phenomenal, I grew to love the Macrodata Refinement team as they became closer over the series. The "villains" are as interesting as the "heroes" - Milchek is honestly one of the scarier characters in the show with his car salesman smile and awesome dance moves. The side characters like Petey and Burt did an excellent job of driving the plot and character development of the main cast despite playing relatively small parts in the show as a whole.
The season one finale left me wanting more - and left with some interesting repercussions for season two!