I see a lot of questions on here that really just need an apparently simple answer like 'because the writers wanted it that way', 'because the author doesn't understand physics', or 'because it looks good on film/tv'.
These questions are all basically the same in that they look for an answer in the realm of the fiction to a question in the realm of the real.
So it seems to me that there's an underlying meta-question to all these which is something like 'why do writers of fiction use seemingly unrealistic mechanisms or outcomes in their writing?' and an associated meta-answer thats something like 'it seemed a good idea at the time' but my question and answer leave a lot to be desired in terms of wording.
So the question I'm asking is what's a succinct but informative way to state the meta-question and what is the succinct but informative answer?