[The subtleties of juvenile word play are evidently not understood--icy BALLS get it--but that's all right, because Sirius is irritated and missing his magic and hating the fact that he's got to miss his magic at all, and sceptical of anyone that takes care of children (something he always resented, when he was a kid, like that was so long ago)....

...but he also appreciates the chance to chuck snowballs at other people passing by. Even if he's still not sure that he appreciates the embargo on an open season, or being told what to do.]

Sorry. I didn't know they were all yours. Anyway, it's just snow, bit of ice, it's not like it's actually going to hurt anyone. Never hurt me.

[He can't help but notice the shift in tone here, though; clearly the loss of magic is something that gets put on everyone, and everyone dislikes it. Misery might love company, but Sirius is a bit selfish with regards to emotion. This is no different.]

Er-- yeah, they said... some things. We get one thing instead of everything, that's a bit of a crap exchange. I think we're getting gouged with that one, who do we lodge complaints with.

[And he adds, as he nods with grudging admiration toward the retreating stranger:] Nice aim, by the way. He got that right in the mouth, he'll be spitting snow for weeks.