FFX ended with you saving the world at enormous personal cost, and if, two years later, the world shows no sign of having been saved, then the original bittersweet ending looks a lot more bitter than sweet. The world has to be brighter, better, moving forward, because you have already sacrificed your main character to make it that way, and if it didn't work, why did the last game say you won?

Oooh, yes! This, very much this. Do you mind if I link it up in the post as an eta?

There's genuine emotion there, too, real relief and desire for change, but I've always viewed a lot of Yuna's public enthusiasm as more smiling while feeling sad.

That's an interesting interpretation, and not one I'd thought about much, consciously. But it fits with her character in some respects, especially considering the things she says about putting on a happy face for the world in FFX. On the other hand, she also learns some lessons in FFX about being able to put herself first sometimes, so I should hope that, as you say, it's not *all* an act.