Every story needs its ticking bomb: Will Luke destroy the Death Star? Will Jack really kill Ralph? Will Gatsby run off with Daisy? Will Chigurgh catch Llewelyn?* We are compelled to keep reading, to find out what happens in the end.
Without this tension, this inherent inevitability, the story flounders, and with no land in sight, the audience is lost, the story a disaster.
*Yes, no, no and no.