Studying body language

The other day, I was on the bus and then the train with a young married couple, and although I couldn't hear what they were talking about, I could tell they were fighting about something. More accurately, the young wife was annoyed with her husband.

I could see by their body language what was going on. He had done something or had failed to do something which had annoyed her. She sat, leaning on her elbow, leaning away from him, while he kept trying to point things out outside the window, looking for some topic that would engage her in the conversation, which would have nothing to do with what he'd done. He kept trying to make her laugh, and she gave him a token laugh every now and then, but her brow never gave away that she was still annoyed. As the husband got more desperate to pull her into the conversation, his motions became more emphatic, he started resorting to cheaper humor until he was finally acting like a complete idiot, embarrassing himself so that she'd have him stop. It was all sadly amusing.