It's not THAT uncommon

so I was walking down the hall at the office today, and I passed one of the "suits" walking in the opposite direction. Polite nod and smile, "Hello," and he stops in his tracks and says, "Lisa, isn't it?"
me: "It's Liz." (just keep smiling. I get this a LOT)
him: "Well, I was close."
me: "It is close. Don't worry, it happens all the time."
him: (puzzled look) "Liz. Is that German?"
me: *blink*
him: "Are you of German descent? Or..."
me: *blink* "Uhh.. English, actually. But... (gulp) it's just.... It's short for Elizabeth. You know, like... the Queen of England? Or ...from the Bible?"
him: "Oh, okay. Queen of England. I like that."
me. (nervous laugh) "...yeah." *run away*

DUDE. This has happened to me once before, but at least when it happened the first time, it was someone from a foreign country where the name "Elizabeth" is probably not very common. But... this guy is obviously a born-and-raised Utahrd (not to mention a business executive with no less than a master's degree) and I find it astounding that he's never heard the name Liz before. Are you freaking kidding me?
So, here's an informal poll:
Aside from yours truly, have you ever heard the name "Liz" before?
Is this guy insane? Or just mind-numbingly stupid?