snake-easing, “Playing Human”
The first and second things that John learned about Sherlock were that he knew more about you than he should and didn’t mind showing off. The third thing that John learned was that Sherlock didn’t touch other people. He didn’t shake hands, not even when he was wearing gloves.
It took a little longer for John to figure out that Sherlock had major issues with dæmons. He often looked at them before he looked at the humans, which was almost forgivable and probably gave him loads of useful information, but John had several times heard Sherlock actually try to talk to other people’s dæmons. It would be shocking if Sherlock didn’t do shocking things roughly once an hour.