Read through MOST of the threads, so if this has been mentioned already forgive me. I'm going to try and trunicate my thoughts as I don't want to get too long winded.
Let me first say that the Flash Sideways being revealed as a Purgatory of sorts was beautiful, resonant and completely straight forward. I wasn't left saying "WTF" or "Huh" afterwards, as it is one of the few instances in all of LOST where Characters actually have something flat out explained to them. Christian told Jack, and us all there was to know about the Sideways, and if you liked it, great, if not, oh well, but for people that didn't get it or are confused by it.... anyway....
My confusion came in the actual Island story itself. I loved this too, and clearly the plot points and what actually happened wasn't confusing to me, but the point behind it all left me quite puzzled. I thought about it all night and day, and suddenly mid afternoon it all clicked and I had an "awakening" of sorts myself, and fell in love with the show all over again. I think I'll do bullets to get the point across as clear as possible.
Here is my interpretation of what events took place and why they took place and how they played into the overall show:
1. Jack Shepherd is a "Man of Science" who constantly needs something to FIX. This aching need often confuses those around him (and often Jack himself) into thinking that he is a Leader.
2. We watch Jack during the first 3 seasons as he LEADS the survivors of Flight 815 with varying degrees of success. His refusal to believe in the Island, his destiny and John Locke shape his character as being stubborn, reason based and flawed.
3. After the reveal that Jack gets off the Island only to become a broken, self destructive man that views himself as a failure, the next 3 seasons show Jacks journey to redemption. He first takes up the reigns of leadership again, but this time with a more purpose driven, faith based resolve. After the failed detonation of Jughead, Jack loses all ability to believe in himself and his actions, and wants nothing to do with a leadership postition. He resigns himself to follow.
4. He follows this until he becomes overwhelmingly certain of his purpose in life. The reason he returned to the Island. What his life has been building to all along. He is meant to replace Jacob. And Jacob has known this too, but needed Jack to come to that decision on his own. HOWEVER, Jacob knows Jack (and all the candidates) better than they know themselves. Jacob knows that Jacks driving force in life is not to lead, but to fix, and that is the job Jacob has always needed Jack to facilitate.
5. Now, before we continue, let us recognize that once the shows big picture became clear it also became clear that Season 2 stood as a metaphor for the entire series. Desmond stuck in his hatch waiting for his replacement to come free him from his job which required him to push a button to save the world symbolizes Jacob being stuck on the Island waiting for his replacement to come free him from his job which requires him to protect a light to save the world. When Locke broke the computer and brought everything to the edge of utter disaster, Desmond did the only thing he could do, he turned the failsafe key. Being exposed to the massive amount of Electro Magnetism made Desmond uniquely resilient to such exposure from that point on. Due to this development, Desmond himself became the "Fail Safe Key" for Jacob.
6. Now, knowing that if things got as crazy for the light/island as they did for the button/hatch he would need his key, Jacob visited Widmore and convinced him to kidnap Desmond and bring him to the island. Widmore followed instructions and once there, exposed Desmond to another blast of EM energy per Jacobs request. This blasted Desmond into the Sideways World, which he realized was in fact an afterlife of sorts. Knowing that this afterlife existed and knowing what it held for him, Desmond returned to the Island world fearless. He had nothing to fear because the Sideways world was waiting for him after this life. Jacob now knew that he could count on Desmond to do what was needed.
7. So Desmond comes into play. MiB believes that he can use Desmond to destroy the light/island and finally go home. Jack believes that there is no way Jacob would have gone through all that trouble to bring Desmond back to the Island if his going into the light would simply destory the Island. So both "Men" lay their cards on the table and bet against each other. They want the same thing (desmond to go down into the light) and both expect that they will get what they want. And, they are both right and they are both wrong.
8. In the premiere of this season, as Juliet was dying, she mumbled about going dutch on coffee, and we well versed LOSTIES assumed that her Sideways incarnation was bleeding through and that we would eventually see a scene where she and Sawyer were reunited over coffee (we cheered..... and waited..... and waited....). But then she said something else. She said she had something very important to tell James...... and then she died. Thanks to Miles' ability to communicate with the dead, he was able to pick up her last lost words... "It worked". At the time we took it to be the first sign that our Island folk might learn about the Sideways world, or at least the first indication that detonating Jughead and resetting the events that led to the crash of Flight 815 had worked. Of course, it hadn't. It was a red herring that made us think what we were watching was the reset events due to Jughead. Well played Darlton... BUT, they had one more trick up their sleeve. At first I was tickled pink to learn that "It worked" referred to nothing more than a vending machine being unplugged and tricking a stubborn candy bar to fall free of its coil. Of all the things that "It worked" could have been referring to, I dont think anybody ventured to guess it referred to Apollo Bars and Vending Machines. BUT, as I have come to believe... it meant a LOT more than that....
8.5 .... Darlton knew that fans would be looking forward to the Sawyer/Juliet reunion, and that it had to be great. And it was, on an emotional level. So much so, that we (or at least I) totally overlooked the BIG clue that was being given to us in that scene. Juliet informed Sawyer how to get what he wanted; the stuck candy bar. She told him that all he had to do was unplug the vending machine, it would reset, and the candy bar would be free. He did it, and when he did, the lights went out, the candy bar feel and Juilet uttered the phrase "it worked". That whole scene was a metaphor meant to shed light on....
9. ... Desmond down in the light. He entered the pool of light, and approached what looked to be a literal cork in the bottom of the pool (but for clarity sake, lets call it a Plug, which has a dual meaning anyway). Desmond entered the pool, unphased by the lights power due to his gift, and UNPLUGGED the light source from the island. The light went out.... It worked. Then ____ hit the fan. The Man IN Black gloated that Jack was wrong and he was seemingly correct as the Island began to crumble right then and there. As the Man In Black attempted to leave, Jack tackled him to the ground and started to wail on him with his fists.... and low and behold, The Man In Black BLED! But it looked as though Jack was right too... Desmond was the key to killing the man in Black. And later, thats exactly what Jack did.
10. So what exactly did Desmond do??? I believe that when he unplugged the island, he reset it, just as Juliet instructed Sawyer to do with the vending machine. Once reset, it took away all the gifts, magic, power of the island and in that very moment, the Man In Black was the smoke monster no more, nor was he immortal... just as Richard seemingly began to age AND, Desmond was suddenly no longer immune to the harmful effects of the light. Which is why he couldn't just go back in and plug the island back in. In order to do that, the island would demand a sacrifice.
11. It was just after Jack had killed the Man In Black, as the Island was crumbling about him that he realized that THIS was his destiny. He was never meant to be the leader of the island, he was only ever meant to FIX it. He destroyed the evil that had corrupted the island, and in order to get it "walking" again, he would have to sacrifice himself by going into the light and plugging it back in. And then the true Island Protector, Hurley could take his place as leader of the newly reset Island that would be a Tabula Rasa for him and his number 2, Ben Linus.
Ahhhhhhhhhhh.... what do you guys think?