In a way, the characters often do take over.
There are certainly times when my own everyday life seems to retreat so the life of the story can take me over. That is why a writer often needs space and time, so that he or she can abandon ordinary life and "live" with the characters.
It can certainly happen that characters in more sophisticated stories can "take over" as they develop and change the author's original ideas. Well, it certainly happens to me at times.
Of course there are big differences in length and character and vocabulary, but each level has its particular pleasures when it comes to the words one can use and the way one uses them.
