John's stirring his tea when he hears a small knock. He's puzzled, but he opens the door. His tea clatters to the floor, but he doesn't care about the spilled liquid or the shattered mug. He looks like he's just seen a ghost.
And maybe he has.
"John, I'm-"
"Sherlock."
"Yes."
"But you're-"
"I'm not, as you can fairly obviously tell, as I'm standing on your doorstep."
John can't say anything for a long while. He stares at the supposedly-dead man before him. His hand reaches out, just faintly touching Sherlock's sleeve. Sherlock smiles. Then-
SMACK!
"What was that for, John?"
"THREE. YEARS. Three years you were gone. You didn't think to write, to call, to somehow let me know that you're alive?"
"I-"
"How could you do this to me, Sherlock? You have no idea how… how awful it was for me."
"John, it was the only way. Everyone had to believe that I was dead. Even you."
"For three years?"
"John, I-"
"No. I don't want to hear it." He pushes past Sherlock and flees out into the street.
"John, wait!"
John keeps walking.
"AND YOU THINK THESE PAST THREE YEARS WERE EASY ON ME, DO YOU?"
That makes him turn.
Sherlock stares at him as memories replay behind his eyes- watching John suffer from afar; waiting for a new blog post that never comes; looking at his phone every five seconds, even though John doesn't know his new number.
"Because they weren't…"
"I thought you were dead!"
"And I knew you were suffering! Do you know how hard it is to watch your… your best friend suffer, and know that you can't do anything about it, and know that it's your fault?" Sherlock runs a hand over his face, through his hair. John has never seen him this upset.
"No… I guess I don't."
"It's hell, John."