"I can't imagine what you and Harry sit around talking about." She was sure it wasn't anything she wanted to hear about. When she was around, she listened. Hermione did a lot of talking, but she was very rarely unaware of what was going on around her, even while engrossed in a book. She knew what they talked about with her around, so she was fairly certain she didn't want to know what was said when she wasn't around. Even if she was a little paranoid that it was bad stuff about her.
Hermione closed her book abruptly, her movements and her expression implied that she was irritated with his questions, but that wasn't it at all. She was frustrated by the lack of answers. She was irritated with the book. "It's a huge phenomenon, Ron. Aren't you even a little curious? This many people sharing this many similar dreams is unheard of. It doesn't make sense. Something not right is going on."