Continuity mistake: After dinner Sam pours Sheila a nightcap, and he opens a (seltzer?) bottle for himself. Sheila leaves, and both her semi-filled glass and Sam's bottle are on the counter. Just as Sam opens a second bottle for himself Rebecca enters, and Sam soon sets his second bottle down near his first. In following shots the amount of liquid in Sheila's glass increases, and Sam grabs his first bottle then walks away, but when Rebecca stands up, Sam's first bottle is back on the counter and it's his second bottle that's missing. (00:20:20)
Revealing mistake: When Rebecca is in the office and throws a drink on Sam, the pattern of wetness changes on Sams shirt.
Other mistake: After Andy leaves with his girlfriend, Diane goes to call the cops. Problem is that when she lifts the phone onto the bar, there's no cord connecting it to the phone jack.
Character mistake: Cliff tests Norm's memory by asking him who the bad guy in 'Herbie The Love Bug' was (presumably meaning the first movie, which was just 'The Love Bug, ' no Herbie in the title, and not the TV series that actually had the 'Herbie, the Love Bug' title). Norm answers Keenan Wynn, and is told by Cliff that is correct and that his memory is OK. Wynn was the antagonist in the second movie, 'Herbie Rides Again' (reprising his role from the 'Absent-Minded Professor'). The bad guy in 'The Love Bug' was played by David Tomlinson of 'Mary Poppins' fame.
Visible crew/equipment: After Sheila leaves the bar, when Sam hops up onto the counter Rebecca exits the office, and just as Sam says, "Hey, let me ask you something, do you think my life is empty and void of any meaning," the moving boom mic casts a shadow on the wall, over the office door. (00:20:35)
Continuity mistake: While Sam considers going to see the psychiatrist professionally just to hook up with her, Carla suggests that he feign impotence, and Sam puts his bottle down on the counter, but it cuts to a closeup with Sam suddenly holding the bottle in his raised right hand. (00:09:30)
Continuity mistake: Diane's outfit (shirt/sweater) changes in the scene where Sam is lighting candles. (00:07:18)
Rebound (1) - S3-E1
Continuity mistake: When confronting coach about Diane coming to the bar, Ted Danson's wedding ring is visible on Sam's left hand. Later in the scene it disappears. (00:15:17 - 00:16:00)
Let Me Count the Ways - S1-E14
Continuity mistake: When Diane turns the TV back on for everyone to watch the game, the TV appears in the background and it's off - this happens twice.
The Girl in the Plastic Bubble (2) - S11-E7
Revealing mistake: When Frasier is on the window ledge the safety line preventing him from falling is visible in some shots.
The Girl in the Plastic Bubble (2) - S11-E7
Visible crew/equipment: When Norm leaves the bar after seeing Frasier on TV the edge of the set can be seen. The brick wall ends and there is a curtain.
Teaching with the Enemy (1) - S11-E6
Visible crew/equipment: The studio lights are visible when Frasier is done with his scotch and says "one more, Woody."
Where Have All the Floorboards Gone? - S10-E8
Visible crew/equipment: In the opening scene when Frasier gets out of his car the camera is reflected in his car window.
Continuity mistake: When Woody gives Norm a beer he puts a napkin next to the beer. The shot changes the napkin is under the beer.
Continuity mistake: During the scene when Norm is giving Doris the letter of recommendation her hair his covering her ear facing the camera. When she says "It must have taken a lot of guts to open up that way." Her hair is now behind her ear.
The Girl in the Plastic Bubble (2) - S11-E7
Visible crew/equipment: After Frasier comes out of Sam's office and goes to sit at a table the studio lights and boom mic are visible. (00:13:15)
Where Have All the Floorboards Gone? - S10-E8
Continuity mistake: After Kevin leaves the blueprints on the bar go from unrolled to rolled up a couple of times between shots.
Where Have All the Floorboards Gone? - S10-E8
Continuity mistake: In the opening scene when Frasier's car alarm keeps going off two people are walking behind him heading to cheers. In the close up of Frasier they are not there.
Continuity mistake: The second time Frasier and Lilith come into the bar Sam is putting ice in glasses for them. Sam finishes the second one and puts it on the bar. The shot changes he is still putting ice in the second glass.
Fools and Their Money - S4-E12
Continuity mistake: When Sam asks Woody to go into the office to talk privately, Woody has no apron on. As they walk in to the office, Woody has the apron on, which then disappears.