Watson: People don't have arch-enemies.
Sherlock: I'm sorry?
Watson: In real life. There are no arch-enemies in real life. It doesn't happen.
Sherlock: Doesn't it? Sounds a bit dull.
Watson: So who did I meet?
Sherlock: What do real people have, then, in their real lives?
Watson: Friends. People they know, people they like, people they don't like. Girlfriends, boyfriends.
Sherlock: Like I was saying, dull.
Watson: You don't have a girlfriend?
Sherlock: Girlfriend, no. Not really my area.
Watson: Oh, right. Do you have a boyfriend? Which is fine, by the way.
Sherlock: I know it's fine.
Watson: So you've got a boyfriend?
Watson: Right, okay. You're unattached. Like me. Fine. Good.
Sherlock: John, I think you should know that I consider myself married to my work. And while I'm flattered by your interest...
Sherlock: I'm really not looking for any...
Watson: No. I'm not asking. No. I'm just saying, it's all fine.
Sherlock: Good. Thank you.