Thank goodness for this thread. Whenever an article about the Lost finale springs up, the comments section inevitably fills with fans who decry those who criticized the show as not understanding the ending or having not paid attention to the answers. While I still think there are some questions that were left unanswered, my biggest gripe with the ending was that the answers it did provide were unsatisfactory and/or were inconsistent with what came before. I'll list my biggest ones here:
1. THE OTHERS. If I were to give an "award" for most disappointing--and inconsistent--storyline, it would be to the Others. They started off so intriguing. Native island dwellers who seemingly were supernatural and who would play a big role in the show's conclusion. Boy, was that impression wrong. Not only did the Others become less and less menacing, they also became less and less important to the story. I still don't understand what their purpose on the island was, why they bothered the losties, why one of them couldn't be the new Jacob, etc. And please don't get me started on the Temple Others-ugh, ugh, ugh.
2. Sayid's whole storyline in the last season, as mentioned above.
3. Claire's whole storyline in the last season.
4.The Smoke Monster and Jacob. The whole "why" of the show was one huge mess. Not only did it not make sense, but it was also cliched as fuck.