Quote from Jason in Tinker, Tailor, Demon, Spy
Tahani: Jason, how did you know that was bad Janet? Jason: Michael said there's nothing he could say that would make you realize he's really him, but Janet does have a thing she can say that does make me realize she is really not her. Eleanor: What? Jason: I called Janet "girl," but she didn't say, "Not a girl." The real Janet always says, "Not a girl." Michael: [gasps] Oh, wow. That realization is the only thing that stopped me from becoming a pile of goo.