James/Harry
James was pissed off. So maybe that wasn't the correct emotion for a wedding reception, but they lost at Quidditch and Regulus was brushing him off, and he was still upset about Toby, and at the moment he didn't want to talk to anyone. He was wondering if he could go home and no one would notice. Hell, he might convince Sirius to get the hell out of here before he hexed someone.
Where was Voldemort when you needed him?
Trying not to talk to people, because that would require not biting their heads off, he walked to the outskirts of the crowd. When he saw his father come his way, he wondered if he could pretend not to have seen him and find Severus, because right now, acidic comments seemed to go well with his mood.