This episode wanted to be like "Ab Aeterno" in that it aimed to answer the mythology of this island, only it didn't come close at all thanks to the poor writing. Indeed, we finally got an explanation of the island's backstory and gave us an insight into Jacob and The Man In Black's relationship which will lead us to the reason behind The Man In Black's motives. It's just that this episode didn't answer everything and still leaves many questions and plot holes. The answers we got in this episode are not really answers. It's all thanks to the lazy writing and ridiculous dialog. There is no subtlety in the nuances, scenes, and interactions that we have always seen from how the show delivers its answers. That's what makes me so disappointed with this episode that could have been so much better than this. I still hold out hope that Lost will end in a better way as the show's great writers have often done. Because I love this show so much.