An essay on io9.com--disturbed over the use of God or other supernatural forces in bringing recent television series to a close (Lost, Battlestar Galactica)--compares Aeschylus' Oresteia and Aristotle to the experience of writing anime:
These stories come from an inherently conservative point of view: everyone has a place to stand and a part to play, and attempts to step outside those boundaries can only result in pain and suffering. You'll notice that stories about God commonly involve triumph over the self, not triumph over an oppressive regime - Arjuna never once thinks that he should share his riches with the lower castes, or that he'll unseat the monarchy once he wins the battle. Doing so would overturn the "natural" order of his environment. Arjuna's kingdom, once he wins it, will continue to rely on slavery to sustain itself - because that's how Krishna wants it. God's role in these stories is a conservator, one who might snip off poisoned buds or gently nudge humans in one direction or another in attempt to preserve that which is good and right, without radically altering anything. God conserves the status quo, and we're supposed to take comfort in that: a place for everyone, and everyone in their place.
Recent American television finales have embraced this logic. The endings of Avatar: The Last Airbender, Battlestar Galactica, and LOST all involve a divine figure returning balance to an earthly equation by repeating an ancient pattern. The Avatar achieves his final state and the four nations again live in harmony. Humans create Cylons, battle Cylons, and become Cylons. The Island calls people in need of personal change, gives it to them, then lets them go (to Heaven) before calling another group. All of this has happened before, and will happen again. The pattern doesn't change, it simply repeats.
Another word for "repetition" is "letdown."
As far back as Aristotle, critics and audiences have measured the quality of a story by (among other things) whether it has a discernible beginning, middle, and end. Things must change. The characters must be in a different place than before, and the audience must feel for them. Traditionally, this comes about as a result of the character making a choice or taking an action that has consequences, and then suffering through them. Agamemnon sacrifices Iphigenia so that his ships might sail to Troy, and Clytemnestra retaliates by murdering him. Hamlet refuses to kill Claudius when he has the chance, and he (and everyone else) dies. Rochester lies to Jane about his marriage, and loses her. Meursault kills the Arab, then awaits his execution. Consequences follow actions. Stories progress. Circumstances change. Characters grow.
But lately on American television, they haven't. Lately, all tension has been drained from their actions, and all opportunities for choice have been robbed from them by fate. Does it matter that humans created Cylons? Not really. They did it because God wanted them to. Does it matter that the Losties all had issues with their parents that they needed to overcome before they could be whole? Nah. They were all in Purgatory, anyhow. Does it matter that Aang had lost access to the Avatar State? No - apparently stray rocks can unblock his chakra. (That's right, kids: Aang works like the Millennium Falcon - a well-placed punch can bring his circuits back online.)