For those souls wandering the Internet like lost travelers in a desert, searching for the Answers to LOST, take your time wandering around my miscellaneous ramblings from Season 6.
Since the conclusion of the series, it is becoming more evident that people will believe what they think "should" have happened than what really happened (or apparently happened) on the screen.
For example, in Doc Jensen's last epilogue, he tries to find closure on the Desmond symbolism with a show referenced novel entitled The Third Policeman by Flann O'Brien. " Now, the link seems pretty clear, at least to my eyes. The Third Policeman is the story of a nameless narrator who realizes at the end of the story that (1) He is stuck in a constantly repeating cycle of unchangeable history from which he can't escape; and (2) He is actually in hell, for he has been dead for the duration of the tale. The natural application of The Third Policeman to Lost would be as foreshadowing for the Sideways world twist."
It is an attempt to explain the Sideways afterlife as different than the Island real life; but one could take his evidence and conclude that both the Sideways and Island events were in the afterlife.
The critical church scene between Jack and his father actually re-enforces that everything was in the afterlife:
VOICE: Hey, kiddo.
[Jack turns around to see his father standing behind him.]
JACK: Dad?
CHRISTIAN: Hello, Jack.
JACK: I don't understand...you died.
CHRISTIAN: Yeah. Yes I did...
JACK: Then how are you here right now?
CHRISTIAN: How are you here?
JACK: I died too...
[Jack begins to cry as he remembers.]
CHRISTIAN: It's okay...it's okay. It's okay son.
[Christian approaches Jack and they hug each other.]
JACK: I love you, dad.
CHRISTIAN: I love you too, son.
JACK: You...are you real?
CHRISTIAN: I should hope so. Yeah, I'm real. You're real, everything that's ever happened to you is real. All those people in the church...they're real too.
JACK: They're all...they're all dead?
CHRISTIAN: Everyone dies sometime, kiddo. Some of them before you, some...long after you.
JACK: But why are they all here now?
CHRISTIAN: Well there is no "now" here.
JACK: Where are we, dad?
CHRISTIAN: This is the place that you...that you all made together, so that you could find one another. The most...important part of your life, was the time that you spent with these people. That's why all of you are here. Nobody does it alone Jack. You needed all of them, and they needed you.
JACK: For what?
CHRISTIAN: To remember...and to...let go.
JACK: Kate...she said we were leaving.
CHRISTIAN: Not leaving, no. Moving on.
JACK: Where we going?
CHRISTIAN [smiling]: Let's go find out.
Christian's statements can be taken into the context of his definition of "real." He acknowledges he is dead, but he is "real" to Jack. And "everything that has happened " to Jack "was real." If being dead in the sideways world is "real," then so to can being dead in the Island world also be "real." It follows one notion that life is not a linear composite of birth, living, dying, death, and an afterlife in heaven or hell. It follows the pattern that once a person dies, he is "reborn" in an afterlife existence consisting of many layers, many attempts to redeem their souls, in order to find cosmic enlightenment.
An overall supernatural afterlife structure makes all the dead end island story lines easier to digest. In an afterlife SAT test, candidates often skip over questions they cannot answer. Some who fail, re-take the test until they get a passing score. Whether this one realm of the dead concept works for the average fan is open to debate.
Juliet's dying thought, "it worked," had nothing to do with Jughead exploding (it probably did not detonate). It is more likely she meant that she found an off-ramp on the afterlife highway, a rest stop, where she would wait for the other characters to finish their island tests, so they could move on together in the afterlife. It makes sense that only a dead person (on the island) could "make a place" in the afterlife where all of their souls could meet in the future (now).