Double, Double, Toil and Trouble - S4-E4
Revealing mistake: As Serena gets hit by the pie her real blonde hair shows underneath, also, she wears minimal make-up for the only time.
The Safe and Sane Halloween - S4-E8
Revealing mistake: In this episode when the Gremlin, Goblin, Jack-o-Lantern, and Sam are peeking in through the back window, the gremlin turns to look at Sam when she is speaking and his ear passes through the area where there is supposed to be glass.
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)
Allergic to Macedonian Dodo Birds - S4-E11
Revealing mistake: When Samantha is on the roof with Aunt Clara, her shadow is visible on the sky background... especially lower left.
Samantha's Da Vinci Dilemma - S4-E17
Revealing mistake: When Leonardo is going through the revolving door his arm/elbow goes through the frame where glass should be.
Answer: Larry had been telling Darrin what it means psychologically that Samantha gave the coat away. Larry said giving it away meant she's happy being married but if she liked the coat it means she desires to be single and carefree. So when Darrin sees the coat, he immediately thinks Samantha doesn't want to be married and the fact that she twitched it means (in his mind) she wants to be a single, carefree witch again.
Bishop73