Revealing mistake: Shortly after the fight with Becky, Roseanne asks Jackie to go across the street to get her something to drink, so she can smoke in secret. After Roseanne lights the cigarette and walks near the register, Jackie's plaid coat can be seen in the door's window as she waits for the next scene.
Revealing mistake: When the family is eating the Christmas cookies, look at the top of the screen. In the kitchen, you can blatantly see where the top of the kitchen actually ends, revealing gray panels. The Conner's ceiling never went up this high, so it is definitely set material.