I'm out of topic ideas so take your pick. What is your favorite Final Fantasy game? Give a reason for better clarification.

I feel like XI is calling me back.

VI
Amazing story, amazing character development, good game time, nice amount of sidequests
Followed shortly by IV for being so difficult. (Wish VI was harder)

FF7.

Grew up on it, Omnislash is awesome, the optional WEAPON fights were brutal, Red XIII kicked ass, Cid's incessant swearing like a 12 year old solo queue rager was always hilarious, and to this day I still despise Sephiroth for killing Aeris.

FF6 is great too, but I don't feel like I really knew the characters as well as I did in 7. Intercepter was a badass too.

FF8. I loved the story and you got to go into space ;D

Super fun using Eden and blasting PuPu to death for tons of damage. Also, Selphie's The End. Use it on the last boss. It's bananas.

Ten
..........What?
Why are you looking at me like that?

Three way tie between 6, 8, and 9.

6: Brilliant, hard to put my finger on the exacts.
8: Different but in a good way. Broke a lot of the fantasy norms while keeping that distinctive FF feel
9: Some of the best overall storytelling I've seen in a game.

A main thing between the three of them is you actually got made to feel for the characters in the story. 7 was good but I never got that emotional attachment to the characters or that yearning to see what happens next like I did in 6, 8, and 9.

Tied between FF 3 and 7. 3 because I enjoyed the story and the characters. 7 because I feel it really made a jump forward evolution and storywise.. also because I enjoy chaining all those Knights of the Round together for a fight and then going to make a sandwich and coming back.

7, because it was the first FF I played, and also the first true deep JRPG I played and finished

at that time I was young and could barely read fluently, and the translation was horrible (I live in EU so I didn't play it in English) that horrible translation plus the fact that I already had trouble understanding sentences if they WERE grammatically correct, added this bizarre, delirium-ish daydream drug trip feel to the game which I remember until now... I haven't re-played the game in English ever since because I want to preserve this unreal-ish feeling memories I have of the game

tl;dr I'm a nerd