To first-time viewers of United States of Tara, one of the most striking parts of the show, besides Tara's kookiness, is how normalized her condition is. People are affected by her DID, but not a way that demands immediate attention. As Tara becomes unraveled in this season, however, there is a shifting tide. Bryce is not a normal alter like Buck or T who act in their own, weird ways but are generally innocuous. He's dangerous in a way that Hatteras realizes. Systematically, Bryce is sapping away the alters one by one until Tara is there for the taking. After a disturbing scene in which Bryce puts crab in the soup to induce an allergic reaction from Hatteras, Tara realizes she has to seek help from the experts in DID, and that regular psychiatrists like Hatteras won't cut it.
Meanwhile, Marshall comes to terms with who Tara is, not a weird person but a flat-out crazy person. His short film reflects all of this, and Max is deeply troubled. While the other plots this week were again rather uninvolved in Tara's plot, Marshall and Max come into conflict and the future is as hazy as ever.
I was surprised to learn this morning that Showtime had canceled United States of Tara and renewed Nurse Jackie (which I stopped after the first or second episode of the second season). I guess the cancellation was warranted since the show only has a couple hundred thousand viewers, but the thought didn't really cross my mind through the season. From what I've read, the season finale does provide a good conclusion for the show which is good even if the show won't return next year.