I'll blame The Princess Bride. The movie, not the book.
My favorite scene in that movie, which I watch far too often, is the scene in Miracle Max's hovel where his wife bursts out of the back room while he's trying to revive Wesley.
It's the first line Carol Kane delivers, and it starts a rapid fire exchange with Billy Crystal that steals the show. Aside from the fact that I could probably narrate the film with the sound off (Seriously, who can't?), it's the inspiration for this post.
Nathan Bransford did a post a week or so ago about how writing is like lying, and yesterday, there was a long and circular discussion about why people prefer to read "fake" stories as opposed to "real" ones. (Long story, but the person in question just didn't get the appeal of fantasy fiction.)
Yes, I'm rambling, and now I'll stop to make the point I had in mind.
Writing fiction is like lying. It's more than the obvious "you're saying something that's not true" parallel. The reader accepts that you're not telling them real facts and suspends their disbelief to participate in the experience. So, fiction isn't lying at all... :-)
The thing to remember in lying and story writing is that the details will screw you up every time.
Lying is a craft. It's hanging a falsehood on the skeleton of truth so it appears different that it really is. Bad liars weight that camouflage down with too many details so that it pulls away and you can see it doesn't belong there. They over compensate by adding things that no one needs or cares to know because they think it makes the lie more believable.
Here's an example:
The Truth: Sonny Boy was late coming home and didn't call because "that place he's not supposed to go" has no cell service, and that's where he was.
A "good" story to tell would be: I'm sorry I was late. I tried to call, but couldn't get service, so I had a friend drive me home.
A "bad story to tell would be: I'm sorry I was late, but I got to studying and the chapter was so long, it took forever. I would have called, but my battery died. Then I couldn't call anyone to pick me up because I didn't have any money for a pay phone, and even if I had, I couldn't find one.
3 unnecessary details that make no sense, and serve no purpose in the story. It's easy enough for mom and dad to know that the library isn't open that late, to check the phone's battery, and to know that the library, were it open, would allow a kid to call home for a ride if he was in a bind.
Fiction writing is the same way. It's a matter of crafting a fine balance in the details needed to sell the story without weighing it down so heavy you choke the narrative. If the reader finds something in the last 3rd of the book that doesn't make sense with the first 3rd (like a character allergic to citrus eating key lime pie), it'll click. You'll be just as busted as that kid who couldn't tell a lie to save his life or driving privileges. (<--- that's a hint right there. If the kid had driving privileges, he would have been able to drive himself home.)
Check, and double check, your details. Make sure that they match beginning to end. Make sure that your characters' actions fit with their personalities. Your readers already know you're lying to them. Your job is to make them forget it.