Sherlock likes some people. Not all of them. Just a few.
Tolerance Levels
Sherlock, surprisingly, could say that he did like Mike. This was unusual because he didn't like most people, finding them unstimulating and clueless. While he couldn't really place Mike into a category that truly set him apart from the rest of the population, he did enjoy seeing him. He had similar feelings towards Lestrade, but due to a history together as colleagues, his tolerance for the DI was elevated.
Lestrade had just left when Mike swept towards him, excitement in his eyes as he sat down.
"I've found you," he said with glee in his brown eyes, "an assistant: John."
Prompt was #18: brown