Honestly, I have no idea where this came from. I came home to work on my psychology assignment (on a completely unrelated topic) and suddenly this popped up and I had to write before it escaped my mind, and suddenly I have a fanfic. It's more of a sort of fictional analysis of Sherlock and John's relationship than it is anything else but I figured I might as well post it. So, enjoy, I suppose.

At first it was a sort of acceptance – a willingness to be acquaintances. Mike Stamford clearly seemed to believe that the two of them would be compatible as flatmates; why else would he have brought an old friend to St. Bart's while he was working? This man was clearly a soldier, going by his haircut and the way he held himself. That was good – a soldier would be used to seeing a large amount of blood and gore, and so he would not be squeamish at the discovery of certain body parts in the fridge. A soldier would also be tidy, which would mean that he would not get in the way of any experiments. On top of that, he was a doctor – an army doctor, no doubt; his medical knowledge could be potentially useful for cases. Yes, it was acceptance, and agreement with Mike Stamford – this man could make a good flatmate.

After that came something more like interest, something of surprise – and that surprise itself was surprising, as people never surprised him. John did. When other people said "piss off", John said "amazing". When other people said "freak", John said "fantastic". John even went as far as defending him, though perhaps not in the best way (that said; John couldn't have known that his claims that Sherlock hadn't taken drugs in the past were inaccurate).

And then John had shot the cabbie for him, ultimately saving his life, and perhaps John could be something more like friend.

Of course, John hadn't seemed to have this same idea – Sherlock said "friend", John said "colleague". Relationships were not Sherlock's forte. Perhaps 'friend' was not quite right. Nonetheless, John was valuable as a colleague. John could follow one lead while Sherlock followed another. John could put in his input; give Sherlock the view from another (more ordinary) mind. John could stand there and listen to Sherlock's deductions, and even respond from time to time (much unlike the skull). John made a good colleague, even if Sherlock had thought friend.

Then John had risked his life for him. John hadn't just shot the cabbie or threatened to shoot the Golem; John had saved his life by putting his own at risk. Sherlock could see the way it would have played out in John's head. Sherlock would have run, just as John had told him to. John would have held onto Moriarty – his sniper wouldn't shoot until he had a clear shot of John, giving Sherlock enough time to escape. But John would have had to let go. Moriarty would have moved away. John would have been shot. John would have died. In that split second, taking a leap at Moriarty from behind, John had put Sherlock's life first, so far above his own. That was not something a colleague did. John had to consider him a friend, too.

Sherlock didn't exactly do friendships, not before John. Relationships were just tedious and unnecessary, and never had he had anyone who could be a friend. Yet John was there all the time, helping him, talking to him, caring about him, and it was impossible to not consider him a friend. He'd say he was his only friend, but that wasn't true; that was made so clear to him that day on the roof. He had Lestrade, and he had Mrs Hudson, and even Molly could almost be considered something like a friend. Yet John was something more than all of them. If they were "friends", the word no longer suited John. There wasn't a word to describe him, but "best friend" had to suffice. Sherlock would have jumped that day even if John had been the only one in danger. Sherlock would have jumped even if there was no way he could have survived. Sherlock would die for John if that was what it took. John was the one person who had so unexpectedly pushed himself into his life in a way that meant he could not see life without him.

Being away from John had only made Sherlock realise exactly how important a part of his life John had become. Sherlock lost count of the number of times he had said something to him before realising that he wasn't there. He lost count of the number of times that he had picked up his phone before realising that he could not contact him, not even to ask him to gather information. A few times, he had even allowed himself the sentiment that came with writing a message to John and saving it to drafts. It was all about the work, about the web, about Moriarty and his contacts – all things he would have sent to him had he been there, working on a case just like they should have been – but once, just once, it was something more personal.

I miss you. SH

Because he did, more than he ever would have expected.

Sherlock had never felt quite as much as he did walking up the stairs to John's new flat three years after his supposed death. John had moved out of Baker Street, settling into cheaper accommodation, but it had not taken Sherlock very long at all to find out where this was. His stomach had felt as though it had twisted into some sort of impossible knot, and his heart had felt as though it wanted to leap right out of his throat. The idea that, after so long, he could finally see John again had made him feel sick and dizzy and overjoyed and afraid and relieved and so many other emotions that he could hardly identify – emotions that had only intensified the moment John's eyes locked on his.

After the initial shock and denial, John had punched him, and he had deserved that. Then John had punched him again, and he had probably deserved that too. Then John had punched him a third time and, okay, maybe he didn't deserve that quite so much – he had done that to protect John, it had hurt him too, it wasn't -

And then John had hugged him, clinging onto him as if he'd never let go again, and he had definitely not deserved that. John was muttering endless strings of words into his coat ("Git bastard I hate you moron I hate you I hate you I hate you I missed you so much"), and Sherlock knew he wasn't quite forgiving him, not that easily, but yet he wasn't telling him to go away and to never speak to him again. In that moment, the words "best friend" no longer fit. "Best friend" was the biggest understatement of the century. There was no lust or desire, not like how John desired the women he dated, and it wasn't even the same thing that Sherlock had felt for the Woman, but yet, as John continued to cling to him, legs giving out with the shock, Sherlock knew that this feeling inside of him, so strange and unfamiliar but so strong, had to be love.