Revealing mistake: When Samantha is showing Martha the washing machine, look at Martha's shadow; it's visible on the "trees" outside the window in the door, making it obvious it is a painted backdrop.(00:05:35)
Revealing mistake: The wires helping the Good Fairy fly are visible as she flies around the living room. They also are visible when Samantha flies outside a couple of minutes later.(00:11:50)
Revealing mistake: Paul Lynde is supposedly "in" the mirror near the front door, but as he waves his arm to cast a spell, the shadow of his arm waving is visible at the far left, revealing he is actually standing off camera at a spot where his reflection is visible. Elizabeth Montgomery also briefly glances at him.(00:02:25)
Revealing mistake: In addition to Samantha, Elizabeth Montgomery also played Serena. In scenes where both characters appeared, Elizabeth would face the camera and play one character and another actress, Melody McCord, would play the other with her back to the camera. But in this scene, when Mr. Beams tells Serena she has a luncheon date with her intended at the rotisserie, Melody (portraying Samantha), with her back to the camera, inadvertently turns her head, revealing her face.(00:07:20)
Revealing mistake: As Larry walks up to the Stephens' house, his shadow falls across the "house" and "street" behind him, revealing that it is a painted backdrop.(00:14:45)
Revealing mistake: When Samantha starts trashing the private detective's apartment, she causes a chandelier to fall onto a coffee table, breaking the table. However, it is easy to see that the table breaks just before the chandelier falls on it.(00:20:10)
Revealing mistake: Aunt Clara levitates her doorknob collection to put it away. As they pass in front of her, the wires used to make them levitate become visible.(00:06:15)