Haha. It's mostly to do with the gameplay as I feel IX hasn't aged as well in that aspect just like the other PS1 FF. Fast forward feels like it's absolutely necessary to play it now. But it still has my favorite Characters and Story by far.

FFXII is my most played one. I loved the seamless combat and exploration was great too. It was the first RPG I played for over 200 hours. So it feels right that it gets the number 1 spot.

First Final Fantasy: FF1 (NES)
Favourite Final Fantasy: It goes back and forth between FF4, FF6, and FF7....but 99% of the time it's FF6.

Final Fantasy games I've played:
FF1
FF2
FF3
FF4
FF4: The After Years
FF5
FF6
FF7
FF8
FF9
FF10
FF10-2
FF11
FF12
FF13
FF13-2
FF14
FF15

Non mainlines are:
FF Adventure (Gameboy)
Vagrant Story (does this count?) (PS1)
FF Tactics Advance (GBA)
Crisis Core (PSP)
Type-0 (PS4)
Four Heroes of Light (DS)
FF Dimensions (Mobile)

You shouldn't have exposed your hypothesis until after results came forward. When you create a thread and set the expectation, people like to stand out and don't like to be predictable. Therefore, I believe that to be part of the reason so many people answered differently.

The first FF game I played was FF7 at a friend's house, but then I later got my own PS1 for Christmas along with FF8 (even though I asked for FF7). So technically FF7 is the first I ever played, albeit briefly. FF8 was the first FF game I finished, and I might consider it my favorite. But I'm also leaning towards FFXIV Realm Reborn.

Good thing the PS4 port have a fast mode =]

Well I'm in favor of making hypothesis and having it prove wrong instead of forcing results to prove it or making hypothesis after collecting data =]

Well for nearly 20% of people the first is still their favourite and considering that there is about 20-30 games in the Final Fantasy series then for 1/5th of them to like the first game they played in that series it does suggest there is some credence in what you're saying, if it was a complete non factor in the picking of the favourite game then that % should be way lower, if everyone who filled out the pole had played all say... 33 titles and the first was one of those 33 games then the chances of the first being the fav should be just 3%. Even most in here have played 10+ titles so the result should be in and around 10% so I think you have a point in your OP findings, the first game does have a higher chance of being liked more.

(based on a rather small sample size still of course)

1) FF 7

2) FF 9 (but ff7 is my second favorite after 9)

3) i played in this order : ff7,8,9,10,10-2,12,13,4,13-2,13-3,type 0,3,15.

Not interested in 1 and 2, as well as the mmos.. Will definetely play 5 and 6 one day.

1) First game was Final Fantasy (NES).

2) Favorite is Final Fantasy 7 (PS1) with Tactics (PS1) being a close second.

3) I've played 1-13, and Tactics.  I also played a ton of other great sequels and spinoffs like Crisis Core, Dissidia, Theatrhythm, etc....  But Tactics is good enough to be counted as a main series game.

I also want to say that I really love Final Fantasy 1.  It was one of my top 3 NES games back when it was a current system, but the Final Fantasy series has improved a ton since then.  Also when I make my "top 50 games of all time" list, I have 7 different Final Fantasy games in there.  The original NES doesn't make it, even though I really love that game.  But 7 other entries do, because Final Fantasy is just that awesome, or at least it was during generation 6 and earlier. 

1. First game was FF2 (Japan 4)

2. Favorite is FF14

3. Played 1-14 (including 13-2 and Lighting returns).

1. FF8
2. FF8 (For a while in 2007, FF12 just barely overtook FF8 but by now it's back to normal)
3. FF1-13, FF15, lots of the spinoff games and sequels. Nearly all of them with FF14 being a notable exception.

My first Final Fantasy is my favourite, mostly because I played the best one first. It was so good I had to go buy FF7 (the only other one released at the time in the UK) and from then on I bought them all as they released. I've enjoyed the whole series so far, but aside from briefly deciding FF12 was the best when it launched, FF8 remains my favourite game ever.

First - FFIV or FFIII, I don't really remember.
Favorite- FFVIII (FFX close by)
Played- III,IV,V,VI,VII,VIII,IX,X,XII,XIII,XIV,XV