I think my story takes the cake:
Harvey Norman, circa 2000
After waiting about 2 months past the release date for Final Fantasy VIII for the PC, I told one of the casual staff wandering around the store what's going on. He said he'd be right back, and got his manager, who uttered some of the dumbest stuff I've ever heard....
Manager: I'm sorry sir, but they have decided not to release Final Fantasy VIII PC in Australia.
Me: Oh well, looks like I'll have to get it imported from America.
Manager: I'm afraid you can't do that. You see, American games wont work on Australian PCs...
Me: What are you talking about? Of course they can.
Manager: No, you're wrong. We have PAL PCs here. They have NTSC PCs over there.
Me: WHAT THE HELL DO TV STANDARDS HAVE TO DO WITH PCs?!
Manager: Well I sell them for a living, so I know what I'm talking about.
Me: Well I program them for a living, so I know you're full of shit.
With that, I walked out. It's incredible the amount of shit a MANAGER spews, one that's supposed to sell these things to customers...
Oh, and I went to another store 10 minutes down the road and found the game on shelf. I haven't bought any computer related stuff from Harvey Norman ever since...