Plot hole: At closing time, Cliff, Norm and Woody spontaneously decide to go to Cliff's house. Sam then enters the bar after his date at Melville's. Later in the scene, Rebecca asks Sam about the 'Three Stooges', to which Sam sarcastically replies that they went to Cliff's house. But how could he possibly know that since he entered the scene after they had already left.
Cheers (1982)
1 plot hole in season 7 - chronological order
Revealing mistake: When Frasier comes into the chalet after skiing he doesn't show any of the visible effects after a hard day on the slopes. Meaning, his face isn't even flushed from the cold, his hair is perfectly combed after wearing a hat and there is not even a drop of snow on his boots.
Breaking in is Hard to Do - S9-E7
Frasier: I thought that Frederick might enjoy himself.
Lilith: Enjoy himself in a bar? He's eleven months old. What kind of values can he learn here?
Frasier: Well, I thought the place had a lot to offer.
Lilith: Oh, please. He'll never learn to speak in this environment.
Norm: [Walks into the bar] Afternoon everybody.
Frederick: Norm!
[Everyone in the bar including Norm has a surprised look on their face].
One for the Road (3) - S11-E28
Trivia: The last line ever in this series was, "Sorry, we're closed."
One for the Road (1) - S11-E26
Question: Is it true they wanted to get Glenn Close to make a cameo as Vera Peterson in the last episode? I swear I saw photos in an entertainment mag of her filming a scene for the final episode, with the joke being Norm's long-insulted wife was actually very beautiful and classy.