Sherlock was walking down the street, brows furrowed as he looked for any clues on his case. He was paying just enough attention to his surroundings to avoid hitting any pillars, or running into tables, but that apparently wasn't enough to stop him from bumping into another person. He turned around to see a blonde man wince and grab his shoulder.
"Whoa, watch where you're go—" He looked up and cut off as he made eye contact with Sherlock. His eyes widened just slightly, and Sherlock could see his pupils grow larger. "Um…" He cleared his throat and looked down quickly.
Sherlock laughed to himself and tilted his head to the side quizzically. "Are you flustered?"
"No," the man scoffed, and started walking away. Sherlock smirked a little and easily fell into step with him, keeping his body turned towards the shorter man.
"You're clearly flustered. Reddened cheeks, even slightly dilated eyes," he noted.
The man suddenly stopped, his face heating up. "What are you, some kind of detective?" he snapped.
"Yes, actually," Sherlock replied easily. He held out his hand and said proudly, "Sherlock Holmes, consulting detective. Only one in the world."
All he got was a skeptical smile. "You're a detective? Yeah, sure."
Sherlock frowned a bit and straightened up. "You're an ex-army doctor, sent home after receiving some sort of bad wound, most likely a shot to your shoulder considering how you held it after I bumped into you," he said in a bored tone, looking him up and down to see if there was anything else he could learn.
The man's eyes widened with surprise. "Bloody hell," he said in a breathy chuckle. "That was amazing." He finally outstretched his own hand, introducing himself. "Doctor John Watson. Nice to meet you, Detective Holmes," he added as a tease.
Sherlock took his hand with a faint smile and a puzzled look. "Please, just Sherlock. Did you just say 'that was amazing'?"
"Well, yeah, it was. I mean, you took one look at me and were able to figure out all that. I call that amazing," John shrugged as though it were simple. "Do people not normally say that?"
"No, they don't."
"What do they normally say?"
"Piss off." John just looked at him for a second, and then laughed lightly. He glanced at his watch and gave Sherlock an apologetic smile.
"I'm sorry, but I'm running late. But, uh…" His cheeks colored a little as he pulled out a little notepad and pen, and scribbled on it quickly. "Here's my number. Give me a call sometime. I want to see if you're really a detective, or if I'm just easy to read." John looked at him hopefully as he held out the sheet of paper.
Sherlock took it and in a matter of seconds had the phone number memorized. "Yes… I'd like that. I know a good Italian restaurant. We could have dinner."
"That sounds great," John nodded with an excited smile. "Alright then. Talk to you later." With that, he hurried off, glancing back at Sherlock only once. Sherlock just stood there and watched him leave, slightly dazed. Once he was gone from his sight, Sherlock snapped back to his senses and went back to working on his case… But not before getting his phone out and adding one Doctor John Watson to his contacts.
Based off of this.