I really enjoy the tone of this. I saw it this morning before the work commute and couldn't resist; the narrative in second-person flows really well here in the best of ways, in a sense of Watson narrating to himself in a sort of mild, but stern self-lecturing.

Loved this set of lines in particular:
He casts aside the scraps of your toast as you lift the cold slices into your fingers and push butter into the crevices with your knife. He will eat nothing else for the rest of the day. You will eat nothing for the rest of the meal, you think.

Love the pacing and symmetry of them, they set such a great sense of tone and atmosphere for the dynamic between Holmes and Watson here. Also a great ending. Wonderful piece, thank you for writing it. :)