It’s been a year of surprises — once again, a rambunctious array of new shows have come out of nowhere to wow us and rattle us and make us glad that television exists. But the best surprise of 2015 might be how good — actually, how great — “The Leftovers” has become.

The show always had its adherents, but I wasn’t one during much of its first season. I recognized the talents of its top-flight cast, but it seemed to have real trouble consistently hitting its chosen target — a terribly difficult target, it must be said.

But I was rooting for it, because “The Leftovers” is part of what might be my favorite TV subgenre: Shows that try to explore complicated and powerful emotional states through keen observation of human nature as well as dream-like symbology. What’s astonishing is that shows like “The Returned,”“Rectify” and the late, lamented “Enlightened” do this so well, given how hard it is to induce a delicate psychological state in the average viewer. Sure, we want to feel smart for decoding a show or even for sticking with one that’s difficult, but most of us also want to be entertained on some level. “The Leftovers” has figured out this tricky balance between what we want as viewers and what we need as human beings: It may be the greatest example of how as show can leave behind most conventions of commercial television while deploying the TV tools it needs with consummate skill. This season, it’s filled with archetypes and strange images and primal moments, but it’s never, ever a slog.

Each time I’ve watched an episode during the last few weeks, I’ve come away thinking it was the best episode in the show’s short history. The verbal duel in “Lens” between Erika (Regina King) and Nora (Carrie Coon) is unquestionably one of the finest dialogue scenes of the year; two women skilled at hiding enormous pain circled each other, looking for an opening, wondering if the person opposite them would be able to find their Achilles’ heel— or supply some comfort. Nora attempting to act like everything is OK and under control is one of my favorite things to watch; it’s like watching a woman walk on a high-wire made of razors. It’s brave, terrifying and insane.

But Sunday’s outing, “International Assassin,” might actually be “The Leftovers’” apex.

As my husband pointed out during the episode, most dream sequences on TV are frustrating because there are  no real stakes; they’re often just time-fillers that demonstrate how much of Psych 101 the writing staff absorbed back in college. But Sunday’s incarnation — which the audience knew from the first moment was a post-death dream-state for Kevin (Justin Theroux) — couldn’t have had higher stakes. He’s been tormented all season by the ghost of Patti Levin (Ann Dowd) and finally he had the chance to slay the dragon, as it were. Their hourlong battle turned out to be every bit as exciting as anything that ever occurred on “Game of Thrones,” and far more disturbing and surreal. 

Silly as it may be to mention, two comedic moments in the episode stand out: After Kevin cut his hand in a fight with another assassin, a security guard for Senator Levin asks if he used Neosporin on the wound. Played utterly straight by both actors, the moment was not just funny, it served as a pressure release in an otherwise taut and tense episode. And it was a reminder that “Lost” — the previous show of co-creator Damon Lindelof — made us care about its characters in part by having them sound and act like regular people, the kind who crack jokes in difficult moments and don’t always exist in fixed, singular emotional states. (It’s certainly easy to imagine Kevin taking to his laptop to write a scathing TripAdvisor review of that hotel: “TV did not work! Staff tried to kill me. Also, towels not fluffy enough.”)

Much later, down in the well, Ann Dowd broke my heart again (somebody please give her a truck full of Emmys). There was a pause as she (and the audience) approached her final moments with Kevin. That dank tunnel — or birth canal, if you will — was suffused with trepidation and not a little love. “The Leftovers” is masterful at taking left turns that add to the jarring mood in the moment, but end up tying things back to the central themes. And so Patti didn’t launch into an elaborate soliloquy full of Deep Thoughts; she told a story about her appearance on “Jeopardy,” which exposed her fear of change (a subject Kevin knows a thing or two about), and tangentially touched on her appreciation of the power of silence.

Thank goodness that silence has been broken this year. Patti and Kevin’s ex, Laurie (Amy Brenneman), have been talking up a storm, in violation of the code of the Guilty Remnant, the least successful element of season one. But I don’t disagree with Patti’s assessment of the importance of quietness and space. The show has found exceptional ways of using silence in season two, with its terrific evocation of Erika’s hearing impairment and with the unspeaking state of Matt’s wife, Mary (Janel Moloney), whose presence doesn’t feel quite like judgment, but there is a watchfulness there.

And of course, there was the wordless opening of the season, in which a woman died to save her child — an act that was bookended by Kevin’s killing of a child, which was, in the end, the murder of a diseased part of himself. Or was it?

(Sidebar: You could view this episode as a kind of inverse of “Lost’s” “Across the Sea,” which also had a mysterious woman, squabbling men, a well and a murder. Both were about adults and children in pain and how that pain reverberates and evolves through time, but the “Leftovers'” evocation of those themes was poetic and beautiful, not clumsy and forced. “International Assassin” worked, in large part, because of what it didn’t explain, as opposed to that regrettable “Lost” episode, which introduced a bushel of questionable ideas into a show well into its home stretch.)

I don’t know what the death of Patti means, and I don’t think we’re supposed to know. I think the idea is to end each episode with with some catharsis but even more mystery, which is a brave stance for any show to take. Very few dramas could take the unknowable and the confusing nature of life as starting points and craft suspenseful, resonant hours out of those raw materials. By loading “International Assassin” with symbols and callbacks — the dead bird, Charon at the gates of Hades (i.e., the hangman on the Jarden bridge), the presence of Season 1’s Holy Wayne and Gladys, Virgil’s cryptic instructions, Kevin’s tripping father — “The Leftovers” immensely enriched what was already an exciting, strange and beautiful episode.

But it never lost sight of what it all meant to Kevin emotionally. I’ll go toe to toe with any “Lost” fan over my devotion to that show, whatever mistakes it made; it was still an enormous and thrilling accomplishment. But “The Leftovers’” second season feels like “Lost” unbound; every episode counts, but in a different way. So much Serious Drama, especially lately, especially in the streaming/Prestige realms, consists of a season full of episodes that look and feel the same, while each “Leftovers” outing is its own odd, engrossing thing (and yet every hour is elegantly linked, thematically and plot-wise). As was the case on the island, each “Leftovers” episode that focuses on one person is like a novel bursting with both ambiguity, terrific character development and unpredictable forward movement, and there’s no need to plan for commercial breaks or keep everyone clothed. (Hey, pay-cable showrunners, on the second season of “The Leftovers,” there’s been more male nudity than female nudity. Just sayin’.) 

For all its tension and forward momentum, the twin centers of the episode were two conversations between Patti and Kevin; the first one thrummed with the question of whether Kevin would kill Patti (or fake Patti, as it emerged). Like many of the best “Leftovers” conversations, it was like a great therapy session: spiky, self-absorbed, self-aware and full of lively expectation. In their second, sadder encounter, I still wondered whether Kevin would be able to kill Patti, and the beauty of that moment was in not knowing whether it would be murder or a mercy killing. (Kudos to Theroux for making me feel bad for a man who’d just pushed a child into a well.)

That supremely earnest and weird scene in the well was a beautiful illustration of the show’s core idea, which is: That which we love the most usually brings the most pain into our lives, but if you avoid that struggle for meaning and connection, well, it’s like not being alive at all. Maybe?

The beauty of this Jungian fever-dream is that just about anyone can put their own interpretation on the doings in Jarden and elsewhere and be more or less right. All I know is, I’ll be thinking about this episode of television for a long time (and laughing at that Neosporin line). Like “Transparent,” another masterful blend of well-honed TV craft and woolly weirdness, “The Leftovers” recognizes that catharsis often comes with a side helping of comedy — or, if not comedy, a wry realization that life is often painful, strange and ridiculous all at once.

For an in-depth interview with Lindelof, look here, here and here