Lifted wholesale from Mike Harrison:
Unable to find a convincing voice, the narrator provides instead a running commentary on her own credibility, making furtive eye contact with the audience, offering & discarding alternative behaviours & engaging in a muddled discussion of her adventures & decisions. In this way she hopes to divert the unanswerable objection, “But surely in this situation–in which the Boobinog is throwing out vast bolts of power-energy & the ponies have no defense shields!–no one who thought like X would ever do Y!” or “Only somebody completely stupid would have gone into that alley in the first place.” It might be described as the motivational fallacy, typical of the aggressive-defensive relationship between failed writers, who dare not trust the reader, & failed readers, who will not trust the writer. For observers of such nightmare marriages, the appropriate question to ask of the writer is, “Excuse me, how many people have ever found themselves in a situation which even faintly resembles your absurd crock of shit?” While, in every case of motivational fallacy on the part of a reader, a similarly direct approach is to enquire, “What the fuck are you talking about ? None of this hokum has the slightest relationship to what you know or how you know it: so either the writer can sell you her crock or she can’t.” In short, it comes down not to credibility but to charisma.