Sokkapow! Aang is glad that Sokka is still pretty much himself enough to joke around with all the time. Sokka's new maturity is a bit of a double-edged sword, I guess. Aang's glad to have someone with experience as one of his best friends, to help him get the hang of the place, but it does also make him feel like he's still a kid sometimes. With fresh memories of Sokka's "oogies", Aang also isn't too keen on talking to him about Katara anytime soon, and he's glad that Sokka remains clueless about that. Above all, he's happy to have his old buddy around to continue kidding around with.