Continuity mistake: In the scene where Gilbert and his buddy's are eating in the cafe. The first time you see the undertakers bowl of cereal, it keeps changing from full to empty several times.
Continuity mistake: In the scene were Gilbert and his friends are in the diner and Gilbert is pouring the salt out onto the table look at how much salt is in the bottle just before the shot switches to Gilberts friends and the look at how much salt in the bottle when the shot switches back. In the first shot there is less salt than in the second shot.
Continuity mistake: In the sunset scene, Becky comments on how Gilbert missed the sunset. Then later, stock footage is used to show his house, and we see that the sunset is still going on. Not only that, but Gilbert's house consists of a single building, while this shot shows more than one building.
Continuity mistake: In the scene after the funeral, you see that Juliette Lewis gets groceries and gets a ride from Johnny Depp. They put the groceries in the back of his truck on the right side under a tarp because it's raining. When they get to her camper, the groceries are now on the left side of the truck.
Continuity mistake: At Arnie's party, from outside the house, Mama is seen looking out between two curtains. Later, from inside the house, she is looking out the window while lifting up a window blind.
Continuity mistake: In the final scene, when you first see Arnie sitting on side of the road his hair appears as it has throughout the movie (long, oily, unkempt). Then he is running down the road towards the motorcade. When he gets to Becky, his hair is cut and well groomed. Also, he appears to be wearing a different shirt. (01:54:00 - 02:00:00)
Continuity mistake: In the scene where Gilbert is talking to his two friends in the diner about Becky, when Gilbert says "Her car broke down or something," his empty hand is up by his face. In the next shot, his hand is down by his plate and he is holding a fork.
Continuity mistake: When Gilbert is in the grocery store when Juliette Lewis comes in for the first time, Mary Steenbergen is talking to Gilbert through the shelf which is open on both sides. At the end of the scene, Gilbert is standing by the shelves and you can see the shelf is closed.
Continuity mistake: When Arnie is playing with the grasshopper in the letter box, the way he grabs the insect changes between a shot and another one.
Continuity mistake: When Gilbert and Amy are unloading the groceries onto the porch, some bags fell over but in the final shot of the scene, all the bags are standing up, even though no-one could've touched them.
Continuity mistake: At Arnie birthday party the mom is inside the home talking to Gilbert. There is a lamp beside the mom on the table every time the camera changes angles the lamp is on and then off at different times.
Continuity mistake: When Mrs. Carver comes to the store to tell Gilbert she is moving, he is ringing up groceries and the register reads $63.69. Right after she asks him what's to become of him, the register is at zero. In the next scene, it is back to $63.69.
Answer: They shot it last and they didn't wear wigs.