Me: "Why did you say that?"
Him: "I'm just playing with you."
Me: "I've been riding a bike in Philadelphia for over ten years, and people keep saying things like that. I can shrug it off on a good day, but it makes a bad day worse."
Him: "I'm glad you're not all that upset."
Me: "I'm enforcing a policy."
Him (looks nervous): "What's the policy?"
Me: "Nobody plays with me for free."
Him (non-ironically, I think): Have a nice night.
Me: Have a nice night.
In case it wasn't obvious, the price of playing with me was that he had a conversation he wasn't looking for.
I'd thought of the "Why did you say that?" move a few days ago. The rest of the conversation was improvised.