Let Bartlet Be Bartlet - S1-E19
Factual error: In the Don't Ask Don't Tell meeting, the USAF Major is wearing a JCS service badge on his right. That is the position for females. It would actually be worn below his ribbons. He is also not wearing a name tag on his blue shirt after he takes his jacket off. That is the one mandatory item required on his shirt.
Chosen answer: A really annoying innate lack of sense. My friends and family say the same thing all the time, and I'm endlessly trying to correct them. I think people just don't know any better and (ironically) couldn't care less that they're speaking incorrectly.