I had a Gifted Education teacher in middle school who just didn't get what was so great about Morrowind when some friends and I were discussing it in class.
There was a lot of "I don't see why you'd spend all that time on a game...."
While I respected the guy, he tended to take things really seriously, which was unfortunate when I tried to show him AxeCop, since I thought he'd be interested in a story written by a kid who's clearly very gifted.
I think his response was "I would have thought it sucked if I didn't know it was written by a six-year-old."
Edit: Oh, and there's my personal favorite, in which I discussed that my sister's roommate had a portrait of Marilyn Monroe, which looked like Metal Gear Solid box art, with my mom as a funny anecdote.
Unfortunately, my mom's brain went: Marilyn Monroe->Porn->Metal Gear Solid is a porn game.