Prompt: I'm sorry (Courtesy of "the ticking clock" – Thanks!)
"I'm sorry, John," Sherlock said, and John could hear genuine regret infused in his best friend's voice. "I swear I didn't mean to-"
"I know," John cut him off. "It was my fault, really." John gently touched the tender bump on his head, courtesy of Sherlock. It had happened like this:
John had come home after work to find a sleep-deprived Sherlock staring out the window, completely zoned out due to his exhaustion. Sighing quietly, John made his way over to his friend and, without thinking of the consequences of his actions, went behind Sherlock and put his hand on Sherlock's shoulder. Sherlock, assuming John to be an attacker, had immediately turned around and punched John hard, knocking him out, and only then realizing who it really was. John had woken up to Sherlock boiling some water in a flask with his Bunsen burner (trying to make a cuppa for John) and apologizing endlessly.
"It was my fault, really," John said. "I shouldn't have gone up behind you like that. Obviously you would think it was an attacker."
"No, John; I should have known it was you. I'm really sorry! I'm so sorry!" Sherlock repeated again, now frantically trying to serve John tea out of a beaker.
By the time John had finished his tea (which tasted surprisingly normal, considering the unorthodox way in which it was made), John was feeling much better and Sherlock was still apologizing. In fact, he had apologized so much that it was beginning to get on John's nerves.
"Sherlock, if you apologize one more time, I swear I'll punch you out!" he finally exclaimed.
"Ok!" Sherlock said. "Alright, alright, fine! Sorry! …Damn."