Steve knew Bucky, very well. Not as well as he'd known him seventy years ago but well enough to recognize when his friend was in pain.
He'd been hiding it pretty well since they'd left Steve's apartment, but now, exhaustion dogging him, it showed in his eyes and the tired slump of his shoulders.
Steve knew enough not to mention it. Even when they were kids, Bucky would never admit to weakness. He'd broken his wrist once on one of the rides at Coney Island, and Steve hadn't even known about it until they were well on their way home.