If you're a "shipper" or just a fan of seeing Losties in domestic situations, SNBH is roughly 41 minutes of pure bliss. Personally I don't consider myself much of a "shipper" (with a few notable exceptions) so parts of SNBH felt a tad slow.
What's interesting to note is the conceptual mirror sitting between the island storyline and the flash-forwards (FFs). In the former, Jack is pulling Kate closer to him as his departure from the island approaches. In the latter, Jack is pushing Kate away as his RETURN to the island approaches.
We're still flashing forward in SNBH but not quite as far as "Jackbeard" as it's called in the LOST community. Now we're starting to see what led him to become such a complete mess. Hurley's having visions and issuing warnings, Jack's seeing visions of his father at the hospital, and the lies held by the Oceanic Six are starting to tear them all apart.
Kate and Jack play house for a good portion of the episode, even to the extent that Jack proposes. But before they can tie the knot Jack's handle on sanity begins to slip. Surprisingly, Kate's the only one who seems to be keeping her wits in this whole ordeal.
On the island, Jack's appendix is causing him all sorts of problems, prompting Juliet and Bernard to perform emergency surgery. The ever-astute Rose questions the timing of it all, Jack suddenly becoming ill just as rescue seems hours away.
Perhaps the most interesting part is the mini-team of Claire, Sawyer, Miles (some great exchanges between the latter two by the way). Claire walks off into the night jungle and sees Christian ("Dad" to her) holding Aaron. This would set up an extended arc for Claire that would essentially skip Season 5.
Matthew Fox really shined here. It's one thing to play a stoic leader or a nasty drunk, but it takes some special talent to play someone in between. Someone who has come to realize the more he tightens his grip the less he's holding on.
I'd say his two highlights were just before surgery on the island and his heated argument with Kate. In both cases he's clearly not himself, the only difference is physical versus emotional anguish.
Evangeline Lilly does her usual superb job, reacting to Jack's bizarre behavior in plausible ways. Once again I must admit I'm not a shipper, but the early scenes between Jack and Kate are very warm without being forced, a credit to both Fox and Lilly.
Bonus points to Holloway and Leung for several humorous exchanges. Sawyer forcing Miles to say, "Yeah, I getcha" always makes me laugh.
Most of the episode is comparatively mild in directorial difficulty and visuals, but the surgery scene is simultaneously disgusting and brilliant. I had to look away from the TV watching it tonight, it was that disturbingly realistic. One might even argue it was borderline gratuitous.
Bonus points for the scene where Keamy almost discovers Claire, Sawyer, and Miles hiding in the bushes. The shot of Keamy's face through the bushes truly sold the intensity of the moment.
Jack's right near the top of my list in favorite characters, but for whatever reason this episode always feels like a calm before the storm. Watching surgery is almost as pleasant as hearing Kate refer to Aaron as her son, so this isn't an episode that springs to mind for a random rewatch.
It's obviously significant that Juliet saves Jack's life on the island, and that Claire wanders off to join Christian, but few other moments were landscape-changers. It may have been nice to see Jack and Kate on the brink of marriage, but Jack was destined to fall apart regardless.
Even as Jack and Kate shared their most intense moments (good or bad), very little of it affected me emotionally. However I will say that if you're a Jack fan it's important to note the fears he discusses in SNBH, specifically fear of failing at being a father. Some critics of Season 6 seem to think David was just a tacked-on red herring but I don't see it that way at all. He was very much a manifestation of one of Jack's unfulfilled desires, one of the most intense internal conflicts he harbored throughout his adult life.
Even though the writers have been very good about keeping island storylines unpredictable despite seeing flash-forwards, SNBH is a case where the conflict was severely dampened by them. It was hard to pretend Jack was ever in serious peril from his ailing appendix given the scenes presented in the FFs.
