Here's the whole scene (I had to watch the episode again on Netflix to get it): --- Sherlock: Why is it always the hat photograph? John: "Bachelor John Watson." Sherlock: What kind of hat is it anyway? John: Bachelor. What are they implying? Sherlock: Is it a cap? Why's it got two fronts? John: It's a deerstalker. "Frequently seen in the company of bachelor John Watson." Sherlock: How do you stalk a deer with a hat? What are you going to do, throw it? John: Confirmed bachelor John Watson. Sherlock: Some sort of death frisbee? John: Okay, this is too much. We need to be more careful. Sherlock: It's got flaps. Ear flaps. It's an ear hat, John! What do you mean, careful? John: I mean, this isn't a deerstalker now. It's a Sherlock Holmes hat. --- Like a boss.