Nothing

He walked on her right, a calculated distance between them, and they remained quiet throughout. She chanced a sideways glance at him, and he looked stiff, as though he'd much rather be elsewhere. The expression looked rather odd on his face, given how she'd become used to their chatting and laughing in the past.

Sighing almost inaudibly, she continued the awkward walk with him in silence, hoping they'd reach their destination soon.

Just then, a young boy of about six appeared out of nowhere, presumably running to play a game with his friends, and bumped rather roughly into his leg. Surprising her, he bent down and beamed warmly at the kid, telling the boy rather amiably to be careful. He told the boy to run off, but not before he gave the kid's shoulder a friendly pat.

She watched him calmly, and marveled at the sight. Now that's the boy I remember...

He looked up at her, almost as though he had forgotten the awkward silence earlier. "You're smiling to yourself. A penny for your thoughts?"

She shook her head lightly. "It's nothing."