The Long Goodbye
When we think of farewell scenes in BBC Sherlock, two things come to mind: The Roof and The Tarmac. Both times it is Sherlock who is going away, leaving John behind. The fall’s echoes resonate throughout the show.
However, there is another pattern as well - John going away and leaving Sherlock behind, even rejecting him. In every single episode after Sherlock’s return this theme is explored, either in the reality of the show or in Sherlock’s mind (no matter what you think happens in EMP and what does not).
For me this has always been one of the saddest scenes in the show. In spite of the violence preceding this moment, John talked at least to Sherlock. After the head butt, however, he drives off with Mary, leaving Sherlock behind, injured and alone.