The Chocobo and Moogle carnival and how it was implemented (as a dream accessible from any save file) kinda hit me, really hard. I mean, say all you want about the (implied) relationship between Luna and Noctis being shallow and all that, but my headcanon around the whole thing is that regardless of whether Noctis dreamt of the carnival before or after Chapter 9, it's really, really just messed up.
He probably spent the entire journey looking forward to finally arriving in Altissia and meeting Luna again. That getting there meant a solution. That it was a destination in itself. Probably dreamt about it from time to time. Getting to Altissia, Meeting up with Luna, figuring out what to do next, celebrating for a while. Maybe it was a recurring dream. Maybe, every time, Noctis woke up with a smile, and continued on his road trip with the bros.
And then they arrive at Altissia. But all too soon, shit goes south. Luna dies, Ignis goes blind, everything is messed up, they have no choice but to keep trekking towards Gralea. And then shit goes further south. And then he dies.
Possibly somewhere inside his psyche, Noctis still maintained this dream of a perfect Altissia that wasn't worrying about the Empire or the Scourge, or Astrals or the Oracle and King or fates or whatever else, and simply just... celebrating. The whole experience of Altissia left such strong emotional scars that Noctis retreats to his ideal, perfect version of Altissia from time to time as a means of coping with what the world and his lineage demanded of him.
And every time, he wakes up back to reality and it hits him that all that isn't meant to be. And he's stuck either in the immediate aftermath trying to come to terms with what actually happened, or post-timeskip where Altissia is but a distant memory because the world is completely screwed by the Scourge and eternal night.
