Length: Short chapters, but ongoing, and going on for a while.
Chapter 1 - Contrary
Sherlock is a strange person. Obviously. But he's strange in more ways than is clear from your first look at him. Much as he likes independence, he hates being alone, much as he distrusts strangers he has no problems with being touched or touching. Despite suffering from the cold and adoring pyjama days, he doesn't own a pair of slippers. He wears Dolce and Gabanna shirts and flatshares, he loves efficiency but prefers cabs to the tube, he finds a lot of people amusing yet rarely smiles with his teeth. It's like he's trying to be contrary.
John is a little weird too, which most people find less obvious, something Sherlock finds dreadfully frustrating. John has punched the chief superintendent of the Metropolitan Police, but thanks cash points on withdrawals. He thinks himself fairly laid back, but prefers to stand than to sit. When he was fifteen, he did work experience at the veterinary clinic in Battersea Dogs Home, but John actually hates dogs. And he's a doctor who carries a gun, there's always that.
Both of them think they shouldn't get on nearly as well as they do.