Hippie, Hippie, Hooray - S4-E21
Plot hole: Why would Serena need Samantha to zap her out of jail? Serena is a witch and very tricky.
Hippie, Hippie, Hooray - S4-E21
Continuity mistake: In season 4 episode 10 (That Was No Chick, That Was My Wife) Louise and Larry met Serena when Sam was explaining why she was home and not Chicago. Then in this episode neither Larry nor Louise know about Serena.
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