This may possibly be the shortest thing I've ever written. Weird that it's in a group of ficlets...

Distance

Sherlock Holmes had never been one to appreciate or even tolerate a physical touch from anyone. Even as a child of three, he never wished to be held in his mother's arms or carried to bed by his father, and as he grew older, Mycroft could be sure that revenge was most effective in the constricted clutching of his younger brother's arm. As an adult, the embrace of a grateful female client only succeeded to be one of the few things that flustered him, and the jovial pat on the back from a Scotland Yard inspector made his eyes narrow. The shake of a fellowman's hand was a common greeting, and so he allowed it without a great deal of argument, but aside from this he preferred to keep his polite distance from others.

In light of this, Mycroft Holmes found it both exceedingly out of the ordinary and oddly amusing when Doctor Watson leaned close against Sherlock's shoulder for a better look into the busy street below his office at the Diogenes, and his brother never so much as blinked at the contact.

Forgot to mention - this is set toward the beginning of Granada's The Greek Interpreter, for those of you who didn't guess.