An issue I think they could've faced (as partners or in general) is Hao being closed off and unreadable. Bin is easy to read, and his emotions and feelings show whether he chooses or not. On the other hand, I feel like unless Hao actively chooses to make his feelings known, he'd be hurt or upset and not say anything but just be irritated. He can be IMPOSSIBLE to read at times, literally a blank wall, so I think Bin might've helped him in that on purpose or not. I think it could've upset Bin having someone like that and not be able to help them or understand them.