Something from Taleb's "Fooled by Randomness":
Then I figured out a personal rule: for writing to be agreeable to do, the length of the piece needs to remain uncertain. If I see the end of it, or if I am subjected to the shadow of an outline, I give up. Think of it this way: would you like to know with great precision when you will die? Would you like to know who did the crime at the beginning of a murder mystery? Actually.. wouldn't it be better going into a movie not having seen trailers/promos, and not knowing the runtime?