I found another list of mine from years ago. I added one to it. Granted, I know the "answer" to some of these is simply you would have no story otherwise, but still...you're "not supposed to" ask. The very fact that questions like these can arise seems problematic to me. Oh well, life goes on...
* Where do the rest of the Transylvanians go in The Rocky Horror Picture Show?
* Why do Doc Brown and Marty take Jennifer outside the car in Back to the Future II?
* Why aren't we using the metric system?
* On the Superfriends cartoon villains ensnare heroes in fatal situations from which they cannot escape except through the help of other heroes. Why don't the villains use these tactics in single-hero shows?
* Why do you park in a driveway and drive on a parkway?
* Who shot J.F.K.?
* What's going on at the opening of The Dick Van Dyke Show?
* Why doesn't Harry Potter use the Time Turner and Invisibility Cloak in conjunction to solve all problems?
* Why did the Gilligan's Island castaways pack such extravagant and abundant costumes?
* Isn't Wonder Woman's invisible plane an air traffic accident waiting to happen?
* Why does Superman pushing a curl down and wearing glasses constitute a disguise?
* Why do they call them apartments when they're so close together?
* In The Flintstones, why doesn't the cat ever appear other than the closing credits?
* House. Houses. Blouse. Blouses. Mice?