George R.R Martin (creator of Game of Thrones) summed it up pretty well:
"By the time we reached the finale, I was still hoping for the best, but expecting the worst. I still think 'Lost' told a terrific story... a terrific story with a terrible ending.
If the payoff had been equal to the set-up, I'd rank 'Lost' among the very best series in the history of television. It didn't, so I can't. So in that sense, maybe the finale did change my opinion of the show.
It certainly made me less likely to go back and watch the series again. If 'Lost' had delivered an ending that tied everything together in some brilliant and unexpected but satisfying fashion, I would have been first in line to buy the boxed set of DVDs so I could go back and watch it again episode by episode, exclaiming with pleasure, "Aha, so that's what that meant," and, "Oho, now I see, I thought that meant X, but it really meant Y." Instead, I fear, watching the series over again would give me more frustration than pleasure, and I'd find myself muttering, "Well, that was never explained," and "Oho, that was a great puzzle that led nowhere," and "Hmmm, that was kind of arbitrary."
Admittedly, I've only watched the show once, as broadcast. Which makes me a casual viewer rather than a devoted fan, I suppose. I haven't made a study of it, haven't read any of the blogs or criticism, haven't subjected the older episodes to any kind of analysis. Maybe I need to do a rewatch. Maybe if I did I would see that I was wrong, that the eventual end was actually being hinted at and foreshadowed in the first season, that all the puzzles are explained if only I looked a little deeper. Maybe.
I have my doubts, though. Unlike Locke, I am not a man of faith. I am a man of skepticism."
