When Bart looks through the mail slot the delivery man has yellow skin and is wearing a light brown shirt and dark brown pants. But when Bart steps out he has darker skin and is wearing a blue jumpsuit. He still has the darker skin color when he punches Bart but in the next shot he has yellow skin again.
The cake that Marge bakes specially for Homer at the start of the episode first appears without frosting, but has pink frosting in the next shot.
Reverend Lovejoy's podium disappears and reappears between shots.
The flowers Lisa throws on the floor in the aisle of the church disappear seconds later.
Homer rolls up the passenger side window from the driver's side while a power window sound is made. This does not make sense since a manual window control is clearly visible.
When Marge is on the phone with Jacqueline, Grandpa Simpson picks up on the upstairs phone to yell "I love you!" to Jacqueline, and Marge ends the call by hanging up. On a land line both phone would need to hang up to end a call.
When Abe breaks the plastic window it shatters and sounds like glass.
When the family is reminiscing about Lisa's third birthday, before Bart and Lisa do their old song and dance routine, Maggie's birthday cake is gone. In the next shot, when the adults are dancing around the table, there is a full cake again.
When Abe brings the woman in the wheelchair to the car, Homer raises the window electrically, but the handle on the door suggests that the windows on the car are manual.