Laura Carmichael' acting
Spoiler alert! Do not read if you have not seen the final episode of season 2 or any of season 3.
I just wanted to take a moment to appreciate how good Laura Carmichael's acting was in the episode where Cora has Spanish flu and then the episode where Sybil gives birth. She does such an amazing job of conveying absolute horror in both situations. Edith is not one of my favorite characters, but I think Laura Carmichael is one of the most talented actresses on the show.