My friends and I were discussing between commercials about some of these unanswered questions. At one point, one of us said, "Yeah, but they're irrelevant. It doesn't matter anymore."
While, I guess that's true to some extent, it just frustrates me that just about everything was left unanswered. Why present it all in the first place if you don't plan on providing any sort of explanation, vague or not?
Because they weren't pertinent to the overarching, main story of LOST.
Obviously, we want to know the answers. Obviously the questions and mysteries preceding these answers were important in their own way to the fabric and tapestry of the story, but not to the throughline of the story, which was about Jack, his daddy issues, and his final resolution of same.
Totally different subject, for everyone:
I also want to say that the burning desire to have every question answered, every mystery explained, having everything resolved and tied up nice and neat with a pretty bow on top is more and more becoming something that I find only arrogant, we-know-better-than-the-people-creating-art nerds seem to be whining about.
Personally, the LOST finale was perfect. The story is complete. And after Christian explained everything, who among us didn't stop for a moment and consider what our own collective flash sideways church scene would be like? All the important people from the most important time our own lives being there as we move on to the next stage. A fitting question to ponder for the series finale I think.
The writers didn't need to answer any of those questions to finish the story. Those questions weren't really important. The emotional payoff was satisfying enough that those other questions, now that it's all over, don't really matter anymore.