Sam and Open
As if Sam would miss the birthday celebration for one of his best friends, not to mention the country that he'd been proud to serve for so long. He knew that Steve hated doing the schmoozing thing, so did he, but it was a necessary part of their lives, especially since they were still doing damage control from Thor's temper tantrum.
He mingled through the crowd, all smiles and cheerfulness, and kept an eye out for any potential trouble.