(possible spoilerish allusions)
I'm surprised this hasn't been commented on more (New Years hangovers?). This episode was (almost) perfect in every way ... the one problem? We still have half a season to go. The way it dealt with the themes of family vs. career ... and how Sarah's backstory so neatly dovetailed into the start of the show five years ago ... it would have been the perfect way to end the show. So what are they going to do with the rest of the season?