The more I think about the ending, the less sense it makes.
That is not a good sign.
Here’s what I don’t understand:
According to Christian Shepherd, “This is the place that you all made together, so that you could find one another.”
But when the dead LOST-ies made “this place,” why did they construct it in such a way that it blocked their own awareness that they were dead? Why did they create a convincing alt-world for themselves where they all had new lives, with no awareness of their past? Didn’t they come to “this place” specifically to acknowledge and let go of that past?
They were the ones who created “this place.” They could have made it anything they wanted. So why did they make it a place that blocked their own memories, when the reason they were there was to process those memories?
Why did it take Desmond to wake them up so they could begin to remember? As matter of fact, why did Desmond even want to wake them up? What was it to him?
Even more puzzling, since they were all initially unaware that they were dead, and thus unaware that they were creating “this place” out of their imaginations, then how did they all synchronize their imaginations to create the SAME place for all of them? Did they attend some sort of Second Life workshop right after dying and before heading out to the alt world, where they hammered out their new world before stepping into it?
It just doesn’t make sense.
I could go on. And I will. But the vastness of the things that don’t make sense is overwhelming, and I must retreat to an alternate reality for a moment. 
Okay, I’m laughing about the Second Life workship…hahaha. I’m sure all the converts who loved the finale would tell you “It doesn’t matter, some things can’t be explained.”
I, too, wondered why they would collectively create this alternate reality and then have to drown and run each other over with cars in order to escape it to the bright light. For those who were happy, why would they want to leave? And if they created this for themselves, why would they make some of the same mistakes they’d made in their previous lives–and then didn’t that mean they weren’t ready to move on yet? Gah.
For those who were happy, why would they want to leave? — Yes. I thought most of the pre-awakening flash sideways stories were both more interesting and more touching than what came after.
I especially liked the story of Jack and his son. I thought that was a fascinating response and resolution to what his life had been like before — and a far, far more satisfying resolution to his daddy issues than Dead Christian calling him “kiddo,” and telling him to let go. Blech.
When Locke told Jack that he had no son, I was so disappointed. I think that’s where my bitterness really took root. Why would the writer’s undercut their own previously brilliant story-telling like that?
And if they created this for themselves, why would they make some of the same mistakes they’d made in their previous lives–and then didn’t that mean they weren’t ready to move on yet? — Yeah. Sayid was still unable to control his homicidal tendencies, even in the sideways world. He hardly seems ready for the bright light! (Though maybe being embraced by Shannon means he’s really in hell — ha ha. ) Also, how come Locke got to get together with Helen, and Hurley with Libby, but Sayid could only look at Nadia from afar? There doesn’t seem to be any consistency to these stories, not the kind you would expect if they were the kind of collective creation that Christian described.
Maybe Sayid was out of the room when they created Purgatoryland because he was still a zombie — so he didn’t get a chance to put in his request for Nadia.
I’m probably going to rewatch the finale some time this week, see if I have a different reaction the second time around, though I tend to doubt it.
Haha! I agree with above comments. And it’s not so much that they left mysteries unanswered…I could live with that. But it’s that in the end, the story didn’t really come together nicely or make much sense.
And if they were dead, why was Desmond’s Penny there? It makes no cents.