I've just finished watching it as I had always wondered what was going on in that peculiar show. I had up until now watched maybe 2 episodes, but heard a lot of talk about it. Was it Mystical/Sci-Fi/Limbo/Dream? I felt that anything that had been dragged out for 6 seasons owed its audience an original, never before explored, payoff.
I watched it off Sky+ this afternoon, skipping over all the adverts (including the mind-manglingly daft one that came right as the hero guy jumped into the air to kill the nasty bald guy... Locke? I don't know anyone's names) and concocted my own theory:
The naturalistic reality (Hospital, Party, etc.) is in a parallel universe from the one on the island. Yes, there was a plane crash that meant that everyone who survived it was "Lost", but because the island was all weird and Bermuda Triangle-ish at the same time another reality spawned in which the flight didn't crash and no one 'met'. The driving force for all this weirdness was some kind of quantum electrodynamic nexus in which the two states of reality and, importantly, the quantum fluctuations that underlie human consciousness were tied at least for those trapped on the island. In this way when people who were strangers in the second reality ran into each other at the Hospital they could recover their lost identities through chance physical contact. Strangers would instantly 'flash' on their shared memories and then invite them and unconvinced others to a Party so more connections could be uncovered.
I thought this was original of them and I fully expected some pseudo-technical exposition to be implied as the Lost escaped from their trap, not by physically leaving the island, but by their very consciousnesses jumping into the bodies of those who had naturalistic lives, had never crashed or met and in all probability - would leave their old island bodies in falling into a coma Matrix disconnect style as they recovered the relationships and shared memories they had Lost from a reality and via bodies that were not their own (only appeared so).
But this was not the case.
The naturalistic reality was Limbo. The Island had been real (although Mystical) and as the hero is seen to die and is joined by "dog" - which everyone knows is a backwards-metaphor for 'goD', you get a whole lame Carl Sagan Contact scenario (you know, where Jodie Foster travels to meet aliens and then she runs into the illusion of her dead dad... groan), and then the dumb hero has to have it explained to him that he is dead (so now we're talking The Sixth Sense) and I have to admit that there is quite a nice touch that the stained-glass window behind them in the Chapel of Rest in which lies an empty coffin has just about every faith covered (and probably themes, like yin & yang - i.e. The Light & The Man in Black / Smoke - that have been interwoven throughout the series, making it an unpin-downable post-modern mystic spiritual metaphor involving meaning, humanity, redemption and the after-life), so when he joins the rest of the islanders in the main chapel it is no surprise that when the doors are opened that they "leave" into an incandescent white light and I am still wondering if the wheel symbol on the stained-glass is something to do with the Wheel of Life and they have taken stock of their lives in Limbo, gained wisdom and are ready to Reincarnate en masse...Phew!
In other words the series may as well have been called: Lost souls.
So, I got it completely wrong. Either that, or they did as the whole "they are all dead and in Limbo" notion had already been mooted, so I expected to not have this confirmed, but subverted in some interesting Sci-Fi way.
Just as well I didn't watch the whole series, I would have been peeved.