The Crackpots and These Women - S1-E5
Other mistake: When the President and his staff stop preparing for his upcoming press conference they decide to meet again "this afternoon" implying that it is still morning. In the very next scene Sam meets with the representative from United States Space Command he tells Sam that at 6:35 AM local time UFO's were detected over Hawaii. That's not possible. Hawaii is 6 hours behind Washington D.C. If it were noon in Washington, it would only be 6 AM in Hawaii, 35 minutes before the time the gentlemen mentioned.
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.