Volunteering and a kid told me his name was Steven but I could call him Steve for short.

I said my name was Bill but he could call me William for long.

That set off a full brain reboot in the kid. 30 seconds of total blank face dead still no one home stare. Finally shook his head and said "what?" Once his brain was back online. I've been laughing about it for weeks.

*names changed but you get the idea.