Here's one that happened to me.

A guy came up to me at work in the hallway. He said "Sharon, I need you to take this box over to xyz."
I said, "I'm not Sharon."
He: "Yes you are."
Me: "No, I'm not."
He: "YES, you are!"
Me: "I think I would know my own name. It's Lisa, not Sharon."
He: "But you've got long, dark hair."
Me: "Yes, so do a lot of people." And I walked away.