Joey becomes a hypocrite when Chandler kisses his sister.

Joey on “The One with Mrs. Bing” and “The One Where Chandler Can’t Cry.”

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On season one, episode 11, “The One with Mrs. Bing,” Joey admonishes Ross for kissing Chandler’s mom.”You broke the code,” he says. “You don’t kiss your friend’s mom. Sisters are OK, maybe a hot-looking aunt, but not a mom. Never a mom!”In fact, Joey seems to really believe this rule when he dates Phoebe’s twin sister, Ursula, just a few episodes later in season one.But after a few years, Joey forgets his own code. After Chandler drunkenly kisses Mary Angela Tribbiani on season three, episode 11, “The One Where Chandler Can’t Remember Which Sister,” Joey is furious — until Chandler lies and says he has feelings for Mary Angela.In season six, episode 14, “The One Where Chandler Can’t Cry,” Joey reveals that he’s still bitter about the whole affair.”I can’t believe Ross is going out with Rachel’s sister,” he says. “When Chandler made out with my sister, I was mad at him for 10 years.”When Chandler points out that was five years ago, Joey replies, “Yeah, you’ve got five years left.”