Something I’ve realized about S3: If you look at it as a trilogy, a pair of bookends framing a central thought, at the very center of that thought you get… this.
This scene is not quite, but very nearly, at the midpoint of ASoT. Everything builds to this, then falls away from it. It’s like the beating heart of the story. And here at the center of this episode, together in 221B, is this lovely, purely happy moment with John and Sherlock in their chairs.
You know, I had sort of noticed that too. But you found the words.