These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Stoic Woobie: Christopher, especially in the last two volumes/episodes.
Unintentionally Sympathetic: Sylvia in the novels is portrayed as pretty much irredeemable. However, since she behaves more sympathetically in the miniseries - such as comforting Tietjens when he has shell shock (in the books she mocked him!) - and since she's played by Rebecca Hall who has very good chemistry with Benedict Cumberbatch, many viewers thought Tietjens should make more effort to reconcile with Sylvia. It doesn't help that Valentine's character portrayal suffered at the expense of Sylvia's - though, to be fair to Stoppard, Valentine was much more developed in the script, a lot of which had to left on the cutting room floor.