Continuity mistake: While Sam and Donna are listening to a TV report that Sam may be heading for Congress, the woman behind him has a phone receiver to her ear, with both hands on the phone. The shot changes and suddenly her right arm is down by her side, but in the next shot it is back in the first position.
Continuity mistake: While Amy is talking to Toby, the piece of shrimp in her hand gets larger and the level of champagne in her glass does down, even though she never drinks from it.
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.