FFVIII, since it's my favourite game of all time.
Literally took me about 10 years to beat because when I first got the game at the age of around 5, I was too stupid to understand the junction system, then years later I played it again and learned it, loved it, but then the game would always crash on disc 2 where Balamb Garden took off. Played it years later again, which was a few months ago, played it from the start to the end because somehow disc 2 magically worked, got to the end and killed the fuck out of Ultimecia.
Finishing that game, was finishing my childhood.
Thank you Square, for making that game.