In season one when John told Jack the island is special and he knows it because it healed him. Had Jack learned that about John, Jack might had expected the miracles he kept seeing on island.
In season 5 episode 7, John gives some interesting hints: 1. To Matthew Abaddon: You say that like it's all inevitable! (Powering the idea that the story is happening within a loop) 2. I'm a failure! (System failure)
An amazing show…just rewatched it after not watching it since it went off the air and loved every minute of it…but the one I could do without is the Jack tattoo episode 😂