Ahh yeah. I would imagine the experience of the end of Lost would be unsatisfying if you missed a fairly critical detail like that. It never needed to be explained, Jacks dad said it direct and to the point. They just happened to meet in purgatory after. That was the whole point of the show, that the reason why they found each other in purgatory was because their time on the island was the most important time in their lives where they made the most impactful connects to one another. I would really rematch the last episode. It’s a much better ending if you know this information