THE ISLAND IS NOT PURGATORY. JESUS CHRIST.

The idea of the island being purgatory has sprung up since the first season, and the producers and writers have constantly denied it. They have said numerous times that the characters are living, breathing people. The afterlife is the alternate universe that was introduced this past season and nothing more. All of the events that took place on the island (and off the island, in the normal universe) actually happened.

I just checked, and it's confirmed in Christian Shephard's dialog during the last scene: "The most important part of your life was the time that you spent with these people." The most important part of his life. These people. Jack didn't meet any of these people until after the plane crashed.

THE SHIT ON THE ISLAND ACTUALLY HAPPENED. Thank you.