Samuel Taylor Coleridge, the poet and author, called drama "that willing suspension of disbelief for the moment, which constitutes poetic faith ..."
Any creative endeavor, certainly any written creative endeavor, is only successful to the extent that the audience offers this willing suspension as they read, listen, or watch.
An author's work, in other words, does not have to be realistic, only believable and internally consistent (see Magic A Is Magic A). When the author pushes the audience too far, the work fails. As far as science fiction is concerned, viewers are usually willing to go along with creative explanations unless the show tries to use real science, at which point it's fair game, though this is because Science Fiction is just that: Science FICTION. Attempting to use actual science to explain something you made up removes the story from its own fantasy universe and places it in the context of reality. That's why people critize your wormhole travel system or how shrink potion doesn't violate the laws of matter conservation. Suspension of disbelief can be broken even in science fiction when a show breaks its own established laws or places said laws outside of fiction.