John had seen many reactions to illness in the past, but he had to hand it to Sherlock; anger was almost original. He'd rarely seen anyone as thoroughly pissed off by a cold as Sherlock was, dosing himself up to the eyeballs on Beechams' Powders and cough syrup while viciously berating the general public for being "diseased cattle". Children and comprehensive schools came under particular scrutiny, as apparently the pre-teen population was guilty of infecting the herd and ought to be shipped off to boarding school in order to keep its plagues to itself.
Truth be told, the colourful ranting almost made his miserable demeanour bearable. A pity, then, that John's offers of assistance were universally met with disdain or petulant fury - "I hate everything, I hate everyone, and I especially hate you" had been uttered when John explained they were out of tissues but he could bring over a toilet roll until he went shopping.
They had barely lived together a month before John started shopping for two without batting an eyelid. Hell, they had barely lived together a week before John had started acting as an interpreter between Sherlock and normal human beings.
It wasn't as if Sherlock was taking him for granted, or even taking advantage of him, really. It was more that Sherlock knew to a certain degree what John would willingly accept, and felt a need to push certain boundaries to see where John's acceptance ended.
John wasn't an idiot, and even if he hadn't trained as a psychiatrist, he could recognise certain behaviour patterns. He just didn't necessarily understand them completely. In many ways Sherlock had the intelligence of an adult - a genius adult - but the emotional comprehension of a child. Anyone that refused to live up to his expectations was an idiot or an enemy, sometimes both, and any study or interest outside his areas of expertise was not worth pursuit.
Medical knowledge aside, of course, though John did wonder how much Sherlock needed his skills as a doctor in comparison with the simple fact of his being a doctor. Sherlock announcing that someone had been poisoned often only carried credence in the average person's mind if John was willing to back up his theory. Lestrade trusted Sherlock's words, albeit with occasional reluctance, but Donovan always waited on a nod from John before accepting any theories requiring medical knowledge.
John allowed Sherlock to use him, as it were, for the simplest reason at first; Sherlock's whirlwind world never allowed him to feel bored. In time there were other reasons - the desire to feel needed, the constant excitement of Sherlock's genius - but the latest and greatest was the surprising realisation that he liked Sherlock. John had been an excellent student at school and as a doctor because he enjoyed finding out how things worked even more than he enjoyed helping people, but time and too many deaths that could have been prevented by simple communication had left him somewhat cynical.
Having someone in his life who could strip away that cynicism, even momentarily, was a blessing. Besides, Sherlock was not quite as sociopathic as he claimed to be - either that, or he was far better at acting human in extreme scenarios than he ever was in day to day life. John couldn't quite decide if Sherlock's behaviour towards him meant Sherlock fancied him or though of him as a brother - more of a brother than Mycroft, anyway - or some slightly creepy pseudo-incestuous combination of the two.
John was perfectly willing to put up with a lot while Sherlock was ill, but the boundary-pushing occasionally had to stop somewhere. Waking up at four a.m. on a Sunday to guitars screeching from Sherlock's room was an absolute no, not only because it was four a.m. on a Sunday and therefore cruel and unusual torture, not to mention technically illegal, but because if he was going to wake someone with music it could at least be good music.
"What the Hell are you doing?" John demanded to know, hands clamped over his ears. He couldn't make out Sherlock's response. "What?" And again, the reply was drowned out. "Turn down that bloody music -"
Blessed silence as Sherlock clicked mute, then, "How are you going to hear me with your hands over your ears?"
John lowered them, cautious of the mute being clicked back off. "What the Hell are you doing? It's 4 a.m. in the morning and I told you to get some sleep."
"I was bored and someone attempted to hack my website. I'm simply returning the favour."
"Why the - whatever that din was?"
"I type faster to distorted guitar for some reason. Possibly as a defence mechanism, I can't stand the sound."
John's mouth fell slack for a moment, involuntarily. "You don't even like that music?"
"If you would call that music, yes."
Realising that yet again Sherlock logic and human logic did not coincide often, John opted instead to return to the original complaint and try reasoning with the madman. "Alright, alright, but as it's 4 a.m., could you please wear headphones?"
Sherlock looked almost perplexed for a moment. "Would you prefer that?"
At last, progress. "Yes. Please, God."
"I'll consider it."
"Good. Don't make me smother you with a pillow."
Sherlock allowed himself a smirk at that, getting up and digging through a box of wires before pulling out a mass of knots with ear buds dangling out and offering it to John.
"I'm ill. Knots are hard when you're dripping mucus."
John sighed, taking the knotted wires and sitting down to concentrate on the task of sorting through them, pausing occasionally to glance at Sherlock as his fingers flew over the keys. John had always envied touch-typists. "You know what helps when you're ill? Sleep."
Sherlock glanced back, smiled, resumed typing.
It didn't take long to untangle the headphones, John placing them down next to Sherlock once he was done, and he almost, almost gave into the temptation to hit him when the response was "Plug those in", before he realised what was going on.
"Stand up," John ordered, doing so himself and pulling Sherlock into a quick hug on being obeyed.
"Shh," John said, patting Sherlock twice on the back for good measure before pulling back from the hug. "There you go."
Sherlock looked positively bemused. "I - only wanted the company," he said, slowly and carefully in a manner that did nothing to help John's sudden, crushing feelings of embarrassment. "But the hug was - nice, I suppose." At least the embarrassment was mutual.
"I'm going back to bed," John said, hands over his eyes. "Where the sane people are. Just. Just ask in future, alright?"
"Ask what? Please, John, would you kindly grace me with your presence?"
"That'll about do it, yes."
There was a long, awkward pause. Sherlock cracked first, his laugh an excruciatingly posh thing, and that simple fact had John cracking up in turn. "Oh, God, I hate you," Sherlock laughed, wiping at his eyes first before stemming the fresh flow of snot with a wad of kitchen roll; John really, really needed to get the shopping done.
"Piss off," John laughed in return before heading for the door. Maybe it was silly to look back, but when he saw Sherlock looking too, he didn't feel quite so daft.
John still wasn't sure a week later whether Sherlock's behaviour meant he fancied him or not, but he had reached one conclusion; sad as it was in a way, given they hadn't known each other for that long, he was apparently Sherlock's favourite person.
When Sherlock asked him out to dinner after John brought home their shopping, the thought had been that yes, there was clearly romantic interest, but their conversation over dinner had been largely dry if not awkward. The final step in swinging him back into uncertainty on the romance front while convincing him of his status as Sherlock's favourite person was when Sherlock leant away from the table, expression uncomfortable, and said, "I hope you don't mind if I pay for dinner. I wanted to - apologise."
John had the distinct feeling Sherlock hadn't made many apologies before. "For what?"
"I can be difficult when I'm ill -"
"- and you were - good. You were very good. Thank you."
John smirked, despite himself. "I am a doctor." He leant forward a little, deliberately catching Sherlock's eye. "You're welcome."
Their waitress took away their dishes with a raised eyebrow, returned with a card reader and a wink, apparently having drawn the same conclusion as their landlady, half of London's police force, and every other restaurant owner they had come across.
John couldn't claim to object to the conclusion. He just wished sometimes he could make it for himself.
And given Sherlock's awkward attempt at giving John a quick hug before climbing into their taxi and sitting as close to John as possible, John rather suspected Sherlock wished the same thing too.