I've always wondered why Goku changes his age here and it's the first big retroactive change. I don't believe in the in-universe explanation that Goku just couldn't count so Toriyama must have had some reason for the change. But ultimately it doesn't matter at all so it's a weird thing to even bring up.
I love how Goku joins in with Roshi.
And there's pay off from the Yamcha fight when Kuririn manages to touch Roshi.
