Of Lost's couple Damon Lindelhof said, "Juliet will always be Sawyer's true love." That says a lot, but finding each other before a candy machine in what might have been purgatory was one of the most emotional scenes ever shown. No quips from Sawyer with Juliet, just love.
This is a major problem we had with the Sideways world: it created David Shepard as a character, just as a way to fake out viewers, and then did away with him as soon as the finale revealed more about this universe.
Jack: Where are we? Christian: This is a place you all made together so you could find one another...Nobody does it all alone. You needed them and they needed you. Jack: For what? Christian: To remember and to let go.