Other mistake: Whenever Charlie is playing the piano, it is clear he really is not. We hear notes playing that his hand is nowhere near at the time.
Revealing mistake: Most of the time, whenever the characters have a hot drink there is nothing in the cup.
Factual error: In Season 9/episode 21, Alan is staying at Lindsey's house when he goes to the basement to solve an electrical problem. He is electrocuted by a fuse box but fuse boxes were replaced by circuit breakers beginning in the 1950s. Lindsey's house as seen in a previous exterior shot is of modern vintage.
Continuity mistake: In many different episodes, there is a ball ornament on the outside deck railing that appears and disappears randomly, almost as if it were completely loose all the time.
Continuity mistake: When anyone goes to Alan's room in Charlie's house, they always exit/enter from the left of the room entrance (when they exit the go left and up the hall then make another left). This doesn't match the floor plan of the beach house though, as the living room has been shown to be more straight out of the room.
Continuity mistake: When Alan first meets Rose, she eventually says "He (Charlie) has a very musky scent" with her head turning to look at Alan. When the camera cuts to Alan, he says "uh huh" and Rose is all of a sudden looking straight ahead. (00:10:40)
Revealing mistake: When Charlie and Jake are at the supermarket Jake tells his uncle to switch milk brands, and when Charlie puts the Dairy Farm 1/2 gallon milk carton back on the shelf it wobbles easily back and forth, revealing it's actually an empty carton.
Continuity mistake: While Alan's sitting on the couch, Evelyn's talking to Alan "helping...through a very difficult time," and in the shots facing Alan all of the books on the table behind him, and also the books on the couch's side table keep changing - not just their position, all the books actually become different books. Additionally, in the shots facing Charlie, the books beside the chair and the books/CDs/DVDs on the bookcase change as well.
Continuity mistake: While Evelyn is at Charlie's asking Alan if he's considered that there may be another man at Judith's "shacking up with her," Evelyn is wearing a blue 2-piece skirt suit, but in Charlie's close-up Evelyn's wearing a white suit with a red floral pattern when she's standing in front of Charlie, at the left side of the screen. (In the original pilot Evelyn is played by Blythe Danner wearing the floral suit, but she had to back out and was replaced by Holland Taylor, who's wearing the blue suit).
Continuity mistake: When Charlie goes into Jake's room and finds all the seagulls, they are projected. There is one right at the front that is very obvious.
Did You Check With the Captain of the Flying Monkeys? - S1-E6
Continuity mistake: When Alan is on the balcony talking to Evelyn, a shot is shown from inside the house. Alan turns away from Charlie and puts his left hand on his hip. The shot changes and Alan's left hand is now in the air and then he puts it on his hip again.
Camel Filters + Pheromones - S1-E12
Continuity mistake: In the scene where Charlie and Prudence are talking about Berta, the amount of soap on Prudence's stomach changes throughout.
I Can't Afford Hyenas - S1-E14
Continuity mistake: After Berta tells Charlie he owes her $74 for groceries, she walks to the table and says 'funny story' with Charlie facing the coffee machine with his head facing towards it. When the camera cuts to another angle, Charlies head is all of a sudden in a different position with no time to have made the move. (00:01:50)
Round One to the Hot Crazy Chick (1) - S1-E15
Continuity mistake: In the scene where the the 'hot chick' is smashing her psychiatrist's car with the baseball bat, a window is already smashed in one shot before we see her smash it in the next. (00:01:35)
Round One to the Hot Crazy Chick (1) - S1-E15
Factual error: When Frankie throws her pills out of the car, she reaches into the center console to open the window. The Jaguar Charlie is driving has its power windows in the door, a place she couldn't reach from her position.
Ate The Hamburgers, Wearing The Hats - S1-E17
Continuity mistake: As Judith is driving Jake home, you can see the fringe of his hair while he is still wearing his beanie. The next shot of him, the beanie is now covering the fringe.
An Old Flame With a New Wick - S1-E18
Continuity mistake: When Charlie and Bill are drinking beer at the table in the bar, the level of beer in Charlie's bottle varies from shot to shot.
My Doctor has a Cow Puppet - S1-E22
Revealing mistake: When Rose scares Charlie, he bangs into the wall and the entire wall moves.
Enjoy Those Garlic Balls - S2-E2
Continuity mistake: Charlie gets a can of drink at the start but doesn't open it. Next shot he is pouring the drink without opening the can. (00:01:10)
Enjoy Those Garlic Balls - S2-E2
Continuity mistake: The level of tequila in the bottle at the start changes instantly depending on the angle. (00:01:35)
Chosen answer: Alan might have thought the bra was too fancy to belong to a regular woman, "I'd love to meet the girl who filled this", he says. He assumed it was one of Charlie's many women.
Eyexpress333