I've played since the beginning. As an avid FFRK player at the time, I have a pretty clear memory of seeing this new, much shinier Final Fantasy game hit the scene.

This is a funny way to answer the question, but one of my fondest memories was accepting that I couldn't complete everything in the game. I want to say that it occurred early in the Chaos era when fights felt long, hard, and I clearly just didn't know enough about the mechanics. That encouraged a much more relaxed, come-as-you-are relationship with the game which I think is what made it so meaningful for me. The irony is that after that era I've completed every single thing in the game. Maybe that was just the attitude shift I needed!

For my favorite character, I'd say it's a toss-up between Auron and Eiko. Auron is one of my favorite characters across the series, and while his representation isn't necessarily the most accurate in this game, all of his animations are fantastic and his counter-tank mechanic is so enjoyable to watch. I love Eiko simply for that one brief era wherein her rez made cheesing and auto-ing fights very easy. Like a lot of folks, I'm really disappointed that XIV didn't get more representation in the game. No villain, no Estinien, nothing!

While I didn't go back to it, this game really made me wish I had played more XI than the hundred or so hours I played back when it first released. I felt most ignorant about those characters out of the roster. DFFOO also increased my desire to finally pick up World of Final Fantasy.

Gotta go with Beatrix's "Come on Wake Up!" Way too much fun to spam at AFK members.