I started as a Dragoon. I don't know why I fell in love with it, despite the fact that any boss that looked at you funny killed you, but I did, and even though I don't play it much anymore (trying to fix that) I still enjoy it a ton.
But, I'm a Warrior main now, and have been since Ramuh was new. I leveled it in 2.0 (I remember the "fun" it was trying to decide whether to hold onto stacks to keep heals up or burn them with Inner Beast for an instant heal. I am so glad that was changed) and while I didn't enjoy it as much as DRG, it grew on me over time. I can't remember the exact reason I chose to main WAR over WHM when I couldn't get any raid progression as a DRG, but I can't say I regret the decision. WAR is just too much fun to play, tanking or DPSing. And then Heavensward came out, and I got to 60...and loved it even more.