I didn't really buy his character change as well. If he was just guarding himself, it would still take a while for him to feel comfortable enough to be 'normal' or 'happy'. It just felt like he was dying to be a joyous person, and the entire time he was training at the Garden he had plenty of opportunities.
So I would have to say his attitude needs a fixing, but only because it changed. He was fine with his 'whatever'.
