This is just a short story - I don't know where the idea came from. I know Sherlock is a little out of character in this story.
Sorry about any mistakes.
"We're not friends." John stated as he entered the front room, the consulting detective looking up from the book that was in his hands, his eyebrows furrowing in confusion as he tried to figure out what it was he'd done wrong. "Well, I might see you as mine, but its clear as hell that you don't see me as yours. So," John stepped forward, tearing the book from the detective's grip so that his attention would be on him, "what the am I to you? Just somebody to help you pay the rest?" John made his way towards the kitchen again, turning behind his chair to face him, "And here was me stupidly thinking that I had formed a friendship with the great Sherlock Holmes, oh," a sadistic laugh escaped the doctor "how wrong was I? Eh?"
Sherlock pushed himself from his seat, trying to shake off the hurt, he stepped towards the kitchen, entering to find John leaning over the sink, "Stupid little Watson." John grumbled, spinning around to face his flatmate, "How stupid was I, eh?" How delusional must I have been to believe that I could befriend you?" Sherlock took a deep breath, searching his memory to try and figure out what it was he'd done to deserve this behaviour from his blogger. "Well, I've learned my lesson. So don't worry, as soon as I can, I'll find a knew place to live and you can have this place to conduct your many experiments and-"
John's rant was interrupted by Sherlock, his voice remotely quiet and childlike as he rubbed as his bare forearm, pain flashing in his eyes as he looked towards the doctor, "I don't want you to leave." He whispered.
"Why?" John questioned, his tone harsh, "Because I help you pay the rent?" He assumed.
"No," Sherlock shook his head.
"Then why?" A silence fell between them, only to be broken moments later by John, "You don't have a reason, do you, Sherlock?" A smirk grazed John's lips as he watched the detective flounder for a moment.
"Do you really want to know?" Sherlock question, his eyes raising to meet John's gaze, "Really?"
"Yes!" John snapped, exasperated.
"I don't want you to leave, because," The detective began in a whisper, "because you're the only person who has ever really cared for me, John, and, as ashamed as I am to admit it, I like it." Sherlock's head had bowed part-way through the sentence, his eyes refusing to meet the ex-soldier's. "No-one's ever cared about me before."
"Mrs. Hudson cares," John pointed out.
"That's different."
"How is it?" John's eyebrows furrowed.
"She's the landlady, John, she has to care about her tenants." Sherlock argued, his eyes raising to meet John's again and the doctor found himself shocked at the red rims around the multi-coloured orbs.
"She doesn't have to, Sherlock." John's tone had softened somewhat, "She could stuff you in here and pretend you don't exist, but she doesn't, does she? Because she cares about you, Sherlock. You can see it in her eyes, her face, the way she touches and talks to you. But you don't notice it." John sighed, running a hand over his face, "How can it be that you, Sherlock Holmes, the world's only consulting detective, can't see when someone cares about him?"
"She doesn't care, John." Sherlock shook his head, his bottom lip protruding slightly.
"Ask her yourself." John felt his anger returning, "You're too caught up in your own world to even notice when somebody cares about you!" John took few calming breaths and gestures to the front room, Sherlock turned entering and sitting on the sofa, "When you were shot," John sat beside him, "who looked after you because you blatantly refused to go to the hospital? It was me, Sherlock, me and Mrs. Hudson. If we didn't care, why would we do it?" A single tear made a track down Sherlock's cheek.
"Perhaps," he sniffed, "I am just too stubborn to see it."
"Perhaps? Perhaps?" John exclaimed, "Sherlock, there's no 'perhaps' about it! You are too stubborn to notice when people are trying to help you because you are so, so used to being bullied." John stated, "Being the victim of crude jokes and ill humour from Donovan and Anderson, you're so used to it, Sherlock, that you can't tell the difference between someone actually caring for you and somebody being snarky and sadistic."
"Its not my fault." Sherlock wiped at his eyes, his gaze meeting John's.
"I know." John sighed, scooting a little closer and handing him a handkerchief from his pocket. "I'm sorry. I'm not going anywhere." John almost gasped in shock as Sherlock leaned closer, his shoulder resting against John's and their thighs touching. They sat together for a while, John quietly comforting the detective as Sherlock rested against him, enjoying the warm radiating from his friend.
Sherlock knew now. He knew what it felt like to be cared about. He couldn't be more thankful for the doctor.