The glove.
AN: not exactly happy with this one. Inspired by an abandoned glove I saw. Please review and thanks for reading.

It was one of the few times we'd seen him with normal emotions because for a second when he was examining the little girl's body he had an expression of absolute fear on his face.
Not horror at the scene, not anger at the child's murder, not the ghastly excitement he so often wore at a challenging crime but pure fear. It was terrifying.

And then it was gone.

He continued in his deductions but more slowly, making sure we were listening, and named the killer and his likely whereabouts before leaving, skipping his usual lecture on bordom and "insufficient stimulus" completely.

I hurried after him, waving my team to start following the lead up, intent on getting some answers.
"What was that all about?" I asked, there was no point being subtle with Sherlock if you wanted a straight answer.
"Sentiment."
"But why were you upset half way though examining the body?" Most people would react immediately when presented with... a corpse like that. But Sherlock isn't most people.
"What did you notice about the victim's hands?"
"They were small, she bites her nails, she was wearing gloves, I don't know Sherlock!"
"She was wearing one glove, Inspector. They were cheap but functional, polyester not wool – likely meaning that the family was not wealthy but had found enough money to buy them. On the hem of the glove someone had sown the letter "R". Someone had cared enough to do that and did it so it would be discrete and not embarrass the child. The murderer took the left hand one, presumably as a trophy"

"But you haven't cared before..." I regretted the words as soon as they came out of my mouth.

"As I said, Sentiment." He was back pretending to being the "fully-functioning sociopath" we knew he wasn't and strode off preventing any further conversation on the matter.

It was a few weeks later when we were performing a "drugs bust" on Baker Street that I noticed a photo on the desk. It was obviously a picture of a younger John and his sister (Harry, Harriet?).
And in the photograph John was wearing gloves with "R" and "l" sewn on them.

I shivered.
And I didn't say a word. Because I had hoped that Sherlock would be Good as well as a Great man, but I forgot how much being Good could hurt.