Misunderstood
Disclaimer: I don't own Avatar: the Last Airbender or its characters.
--
It was on one of those days that Sokka ran into the other boy and he just didn't understand.
He didn't understand why Mr. high-and-mighty had to go around and announce he was angry. Its not as if people cared that he was angry or not. He guessed they really did care but only when the firebender crossed paths with them (or worse they with him) when he was in this mood.
At first Sokka was thrilled to have someone his own age (Haru didn't count on the fact of his mustache and matching goatee) but if Zuko didn't get out of his moody stoop soon then no one would want to be his friend. Zuko would be needing friends if he wanted to survive his sister for much longer.
Sokka just didn't understand why Zuko was PMSing half the time. He decided, though, if he wanted to do something about it he would have to take the first step.
And that's exactly what Sokka did.