Via The Science of Johnlock
It happened on that dusky evening after the funeral. John entered the empty flat and dutifully made himself a cup of tea (though what he really wanted was some dutch courage) and stood by the window, watching the rain splatter against the window. Something caught his eye and he looked around and he saw it. Staring at him. It was that face, that bloody face that Sherlock had graffitied onto the wall after the Banker case.
It was smiling at him.
John felt unexplainable rage bubbling into him. How dare he. How dare he look so happy. How dare he smile when everything in John’s life had broken, shattered and splintered like fragile china smashing on the floor. John wished that he had his gun, so that he could shoot the face; just as Sherlock had done so many months ago; and maybe, maybe then it would stop smirking at him.
But then again, he didn’t. Because he knew that if he had that gun in his hands he would do something else, something rather more permanent.