Arcs are good. They keep a series moving at a good pace, give it a greater sense of purpose, unity, and forethought, and generally help keep up interest in the story as a whole. Unless they go on and on. And on. And on. For months, if not years. When this happens, a story has succumbed to Arc Fatigue. Possible reasons for this are: Note that in particularly ridiculous examples, a series may suffer from Myth Stall because it's laden with Filler Arcs suffering from Arc Stall. Examples of Arc Fatigue include: