I don't think I'd really thought about that aspect before.

It was something I couldn't stop thinking about right the way through. I know the story was about them and their relationship. Obviously. But the way people interract with their environment shapes them, their reactions, their thoughts and so on. The lack of interraction with others (their good friends and colleagues), and the lack of any comment by anyone on their very unusual situation, felt pretty weird to me. I kept waiting for it, but it never came.