The handwriting on the list that Ruth has made of Bob's assets changes several times throughout the movie.
Ruth's dress changes colors from the time she leaves the house prior to the explosion to the time the house explodes, then back to the former dress when she escorts Andy and Nicolette away from the rubble.
When Bob is taking a shower and sees Ruth through the shower door, he screams. He steps out of the shower, and Ruth tells him that she is there to weigh herself. Bob walks out of the bathroom, and Ruth steps on the scale. It's not visible but its motion is audible like it's a rotating-dial scale. But when the camera shows the scale to show the audience what she weighs, it is a digital scale.
When Bob picks up the mail from the mailbox, the pink envelope he hands to Mary has no stamp on it.
In the opening scenes, when Roseanne is trying on the gold-and-black minidress, she turns 3/4 to the camera and we hear the dress's zipper and she looks satisfied at finally getting it to zip up. But in the mirror on the left, the dress is still half-unzipped and her bra is still showing as much as before.
When Bob is being helped into the police car while being arrested, a voice says, "Watch your head, sir," but he's already in the car and a policeman is getting into the car when the line is spoken.
At around 43:53, the kids' dialogue does not match their mouth movements.
When Mary Fisher is making faces in her bedroom mirror, the cameraman's shadow is visible on her reflection after she puts her white brush down on the dressing table.
When Ruth boards the bus headed for NYC, you can briefly see Hooper standing off to the back of the bus before she begins sprinting after it.
When Ruth burns down the family home, she leaves what looks to be dozens of signs of deliberate arson. The insurance investigator would quickly determine it to be arson, and Ruth would have a warrant out for her arrest. Yet it's very clear that she doesn't.
The People Magazine article written about Mary says her parents married in 1941 and gave birth to Mary three years later, making her either 44 or 45, but in an earlier scene, Mary's mother says she's 41.