He rather thought that their unusual closeness was probably part of the problem. Hermione was right there in front of him, or next to him, all of the time. And he had just grown so used to her being there, supporting him, checking him, becoming the voice of reason in a mind of chaotic recklessness, that he'd overlooked so many of the more obvious things that she was becoming to him. But some part of his psyche had realised it, and he had fallen in love with her for just that, without even consciously knowing that he'd done it.