Disclaimer: I do not own Sherlock.
How to: Train Your Detective to Cross the Street.
John was almost certain that he'd nearly had a stroke the first time Sherlock had crossed a street— in London, mind— without looking both ways. He'd run after him, nearly getting hit himself, only for the detective to look at him like he was a madman when he started yelling.
"John, calm down!" Sherlock ordered him, grabbing his shoulders. "Why, exactly, are you shouting at me?"
"Did no one ever tell you to check before you cross the street?" John demanded in response, squirming away from Sherlock's grasp, heart still beating out of control.
Sherlock stared at him, puzzled. "Check what?"
"To see if there are cars coming!"
"Oh that? They'll stop," Sherlock replied dismissively.
"You look around. All the time, at everything. Except, apparently, when crossing the bloody street!"
"Looking both ways is dull."
"Being in traction is dull, too, I'm sure."
"It's not as bad as you would think," Sherlock contradicted him. "Generally, if you're in traction, you're heavily medicated enough that you don't much care that you can't move."
"Why were you in traction?" John demanded. Then he thought better of it. "No, you know what, I don't want to know."
Sherlock gave him the look that John was most used to receiving from him— a vague lack of understanding mixed with mild horror.
"One question, actually," John amended. "Were you in traction because you were hit by a car?"
"Well, next time you will be. Promise me you'll look before you cross the street, from now on? That's all I ask. You don't even have to wait if you see a car, just take a look first."
Sherlock turned and began walking. "I don't make promises I can't keep, John," he called over his shoulder.
John gaped after him until it became clear that he was going to leave him behind, as he so often did.
"Sherlock! Wait for me!"