Continuity mistake: The jacket that Violet wears has a zip. However, this zip disappears without trace once she is a blueberry, and remains missing for the rest of her existance as a blueberry. Violet's body was done in CG animation, so it could not be that Violet had to change into a different costume. There was no reason why the zip couldn't remain, it just seems like the CG makers got tired of it being there.
Other mistake: In the beginning of the song about Augustus Gloop, computer generated Oompa Loompas can be seen running through the Chocolate Room, preparing to sing their song. In the DVD release, some Oompa Loompas can be seen running to places that no real person could possibly stand on. This mistake was later corrected in the Blu-Ray release.
Other mistake: Squirrels are used in the factory to get nuts out of shells. Mr Wonka states that they tap the nut first to make sure it isn't a bad nut. However, this is never done until the action is pointed out.
Factual error: In the scene in the glass elevator, when Mike Teavee wants to push a button, he presses the TV Room button. The elevator stops going down and immediately moves horizontally. The characters within the elevator are thrown against the wall from the sudden change. However, they are thrown against the wall that is in the direction the elevator is now moving, instead of the opposite wall as they should have been. (01:20:15)
Continuity mistake: At the beginning of the movie, the Golden Tickets are placed over the upside-down chocolate bars, meaning that the tickets are actually on the bottom, but later when the children find the tickets, they are now on top of the bars.
Visible crew/equipment: When Charlie is shining Willy's shoes near the end, you can see the reflection of a crewman in Willy's glasses when he glances to his right. (01:38:25)
Factual error: In the scene where Wonka is flashing back to his childhood, he finds a chocolate that fell beneath the fire grate in the ash. He opens it and eats it unscathed. Knowing that chocolate can melt around even the slightest heat, there is no way the candy would have survived the heat from the fireplace being just inches away.
Factual error: When Augustus is caught in the tube, chocolate sprays out from a leaky connection. The tube was under a vacuum and the bottom end was open to the river below, so pressure could not build up either above or below him.
Continuity mistake: In the scene where Mike Teavee has smashed up the red pumpkin-looking thing, he smashes it cleanly into two or three quite big pieces. When his father says "Mike, please" the pieces behind him are much smaller and all over. (00:41:35)
Continuity mistake: During Mike Teavee's scene, his father has some bits of hair overlapping the arms of his glasses. On the right side the bits appear and disappear from shot to shot.
Revealing mistake: When Augustus is leaving the factory, he is wearing a brown colored glove on the hand he gnaws on. You can see the seams in the glove.
Continuity mistake: During the scene in the chocolate room, Violet's mother has red, sticky candy all over her teeth and face, visible when she smiles at Mr. Salt. A few seconds later, all of it is gone. (00:42:25)
Continuity mistake: At the nut factory, when Mr. Salt is there with the ladies, and he is walking up to the podium, the microphone is facing towards where he is walking from. Then in the next shot when he is at the podium facing the ladies, the mic changes direction and is centered, facing him.
Continuity mistake: Willy Wonka is bobbing his head to the Oompaloompa song in the nut room. But when the shot pans out, he is perfectly still.
Factual error: Dusseldorf does not, nor has it ever, looked like the quaint place shown in the film. The caption does get quite a laugh from German audiences, though. The place shown is the town of Gengenbach.
Continuity mistake: When Veruca is choosing a squirrel, she heads for the last one in line, furthest from the ladder. Then after it cuts away and back, she is headed towards the middle of the line, but then she is headed for the last one again. When the squirrels jump her, she is about 1/4 of the way down the line, starting from the ladder.
Continuity mistake: After the boat ride, when the boat settles in front of the door to the Inventing Room, Charlie's hair is windswept from the ride. In the subsequent close-up scene, however, his hair is suddenly kempt again. (01:01:30)
Continuity mistake: After Augustus Gloop falls into the chocolate river, he gets sucked into the current of the pipe. At one point in the scene, a yellow bush seen in the background is moved back and forth by the current, but after the next cut, it is seen motionless.
Continuity mistake: When in the Chocolate Room, Mike Teavee crushes the pumpkin into three pieces. It then zooms out and shows him crushing it into three pieces again when Mr. Teavee comes up.
Continuity mistake: On Charlie's birthday night he breaks up the chocolate bar into pieces and gives them to his family, when he gives a piece to his father the piece is in two pieces but when his father starts eating it, it is in one piece.
Answer: Wonka is simply uncomfortable around people. Gum chewing is simply an annoyance he never had to put up with as a recluse.
JC Fernandez