The Achievement "Walking on Sunshine" is for Completing the quest "I Believe I can Fly" which grants your personal or Fat chocobos the ability to fly.

The achievement gives a title reward of "Finder of False Gods" ... seeing as how we took our chocobo around Coerthas and Dravania, killed some mobs and let it breath the fresh air, I fail to see how it has anything to do with deities of any kind.

It feels like the title belongs on a different achievement for a Main Scenario quest instead of one about chocobos.