At the library.

A patron wanted to see my ID badge, but I was unwilling to show it.

• Patron: I'd like to see your ID badge.
• Me: Why?
• Patron: Because you serve the public and I want to know who you are.
• Me: Show me your ID first. I want to know who you are. If I serve the public, and you are the public, then I need to know who you are.
• Patron: No. I am the public, therefore my personal information is private.
• Me: Hmm. Your kung fu is greater. You have won this round.