For me it is the end where I have to wrap everything up, tie everything together, and bring the story to a close while leaving an opening for the next book to follow in the series. I re-wrote the ending of In the Shadow of the Dragon King about 4 times before I got it to where I was happy with it.
Too bad we can’t keep ‘re-writing’ real life until we get the ending right, eh? 🙂
An odd twist to all of this, though, is that I wrote the ending to the third and final book in the Chronicles of Fallhollow series before I ever wrote a word on the 1st book, and I refuse to change it. I think I am happy with this ending because it is truly ‘the end’. With the 1st two books, there is no real ‘end’, only a continuation, and it takes that perfect ending to make readers’ want to wait a year or more to read on. I hope I have accomplished this with my first novel.
So, what is the hardest part of your novel or story to write, and why?