Okay, work with me on this one.
Season 1 was all about the characters realizing that the island was not a normal place, leading to the discoveries of the hatch door and the indigenous people known as the Others. Result: those dreams of normalcy end with two explosions: opening of the hatch and the destruction of the raft.
Season 2 was all about the Swan. Season ends with the destruction of the Swan with an implosion.
Season 3 was all about the Others. Result: Others are "destroyed" by explosions. (This one is arguable since many survived and remained a powerful and yet weakened entity. Their mystical superiority over the crash victims had mostly ended though.)
Season 4 was all about the freighter. Season 4 ended with the explosion of the freighter.
Season 5 was all about the past/time travel (again, this could be argued). It ended with the destruction of the past/present that they knew via an explosion at the Swan.
Season 6 has been focusing on the smoke monster. Is it a stretch to say that season 6, and LOST's endgame may be the destruction of the smoke monster?