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.
Let Bartlet Be Bartlet - S1-E19
Continuity mistake: When CJ leaves Toby's office and Josh sits town on the couch next to Toby she closes the door as she walks out and we can hear it close. But the camera switches to a different angle as Josh sits down and the door frame is still in picture and is open as we hear the sound of it closing the door frame is still open. (00:20:40)
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.