Here's a few "what's the deal?" things that make sense in real life, but work better in the works of fiction they occurred in.
*In "Big Fat Liar", there's a trailer for a ficticious movie of the same title... But it hadn't even started production yet. Even though the trailer in question wasn't meant to be an actual clip from the movie (or was it?), why would a studio put out a trailer for a movie before the movie has even started filming (I was going to ask the same about putting out trailers to movies that haven't even finished filming, but I recently learned that the Angry Video Game Nerd Movie hasn't finished filming yet but a trailer was posted months ago)? If the film gets canceled (and in the movie it nearly does) then it's a waste to show a trailer.
*In the "Simpsons" episode "The Itchy and Scratchy and Poochie Show", Homer refuses to read Poochie's lines if they involve him getting killed, and prepares his own lines, which he gets to do because the voice of Itchy and Scratchy stands up for him, and the shows staff appear to like the dialogue. But then when that episode airs, the voice is badly dubbed and the scene badly animated so that Poochie does die after all. But normally in animation (at least in countries where the production is based in) the voices get recorded first and then they get animated. They could have animated it better, but also I feel they could have easily kept the line Homer wrote, and THEN had Itchy and Scratchy kill Poochie. In fact the Itchy and Scratchy show is based on Itchy killing scratchy, while the first Itchy and Scratchy and Poochie episode had nobody get killed.... They could have kept Poochie on and either had him killed regularly or had him kill Scratchy.
As I said, those things work better for the plots.
Here's an observation which was once pointed out by Peter Griffin: On How I Met Your Mother, how come they have Bob Saget as the voice of future Ted, when Ted is already an adult? Have the creators ever given any official explanation?
And also on How I Met Your Mother, how come it seems like they'll show the kids in some episodes, then go many, many episodes without showing them, but then show them again? I know that since season 2 the same footage of the kids were used every time (and I've read that they shot something with them for the last episode). At first when I noticed they stopped showing the kids in every episode I thought they dropped the kids, a good idea so they wouldn't have to worry about them aging (and wouldn't have to pay the actors who would just appear for a minute at most per episode).
In an episode of King of the Hill, I think the episode is titled "Lucky's Wedding Suit", Dale gives Lucky a job and after he gets injured on the job Lucky sues Dale. Hank points out that Dales insurance (can't remember what kind of insurance) would cover everything, and then checks to make sure he has that kind of insurance, to which Dale complains that he does because Hank made him, and then thanks him. This implies that he wasn't lying about the insurance... But then a scene later Dale realizes he does not have that insurance. Maybe I missed something, but what happened there for him to not be covered?
And in the episode "The Accidental Terrorist", everybody except Hank seems to know to pay less than sticker price for a car, but Hank had been "scammed" four times into paying sticker price for cars, after the car salesman had told him that paying sticker price is a deal. But do people really expect to pay less than sticker price for anything? How can a person realistically buy a car and expect to pay less? At least the salesman didn't trick him into paying more than sticker price. Of course I've never paid for a new car (all of my cars belonged to my parents first) so maybe there's truth in television I don't know.