Can we talk about this moment? Call me a Sora fangirl, but I just see emptiness in that smile; and I have ever since the first time I saw it.
Don’t get me wrong, Sora is honestly enthusiastic for Riku becoming a Keyblade Master. But the moment we see them outside, Sora is almost a little too enthusiastic. And honestly I think he’s doing it to keep himself from crying. He’s happy for Riku, but I do think he’s extremely disappointed in himself. As the fandom often brings up Sora “is too happy”, I often reply saying that Sora staying optimistic is the only way he knows how to deal with things.
If you were 15 years old with the weight of the UNIVERSE (not just world in his case), wouldn’t you be overwhelmed? Sora may act cocky sometimes, but his true colors come out sometimes, especially in the scene in Hollow Bastion in KH2. When the situation seems hopeless, Sora says “Maybe everything we’ve done, maybe it was all for nothing… What can I do if I can’t use the keyblade?”.
This just shows that he’s had his doubts here and there along their journey, and on top of that he’s just found out that at the cost of keeping people safe by defeating the heartless, he’s also helping the Organization. If I was Sora, I would probably burst out crying right then and there. And when Riku takes away his keyblade in KH1, Sora kinda feels hopeless there too until Beast says he’s going to keep going. With that as motivation, Sora replies, “Yeah, I’m not gonna give up now. I came here to find someone very important to me!”.
So in my opinion, Sora’s optimism, along with the bonds of his friends, are really the only things that keep him sane in times of extreme stress. This is also why I think the Keyblade War (13 darknesses vs 7 lights) is going to be a very, very rough battle for Sora. If anything serious happens to his friends, he will definitely lose his composure. And maybe he will show the ‘anger’ that you all have been waiting for.