"I..." Sherlock started, then shut his mouth. What was it about this man that set him back on his heels, that literally made him speechless?

He could deny it, sure. But what good would that do? He had taken every opportunity he could in the museum to study everything about John- his look, his sound, his smell, how he reacted to certain stimuli. In some ways he could read John like a book, but when it came down to brass tacks, he knew nothing about the man.