Things that make me happy in game...
My house in Mist
Seeing Limsa or the Mist residential area on a clear sunny day
Finding a gathering node with +2 extra hits when I have full gp to take advantage of it right away
Screwing up my crafting rotation but still get an HQ even with a low chance
Healing that one huge pull in Gubal expert that starts with the frogs at the bottom of the stairs all the way up to the library room with the statues in one big clusterf**k of aoe, healing cooldowns, and dodging aoes... and everyone not only survives but doesn't even break a sweat (requires a good tank & dps he he). ^_^
The fact that there is such a huge over-arching story from your character's humble beginnings to the epic battle with "the Gryphon" that we most recently got to engage in. It's really making me look forward to Stormblood. ^_^