If I say "Wow, that's crazy" for a second time, that means it's time to wrap up your story. The first "wow, that's crazy" is polite. The second one is a hostage negotiation. Everyone has been trapped by a talker, and everyone has a go-to phrase for surviving it. Shoppers read this, recognize their own move, and immediately think of the coworker, in-law or neighbor it's meant for.
