As Chuck Wendig says in his book, Damn Fine Story, a good story consists of fire and oxygen. The fire is exciting and maintains the reader’s tension while oxygen provides the necessary rest.
The role of oxygen is not only to give time to breath, it is there to allow the next fire.
Stephen King is a master of this technique and one of the good examples is found in the book Bones of Bones.
For the better part of the book, Mattie Devore, with the help of Mike Noonan, fights for custody of her daughter against an evil father-in-law, and that’s where all the fire of this piece lies.
Oxygen arrives the father-in-law’s death who left Mattie $80 dollars. Everybody is happy, breathing, having a barbecue, until Mattie is simply shot in front of everyone (except her daughter, whom King put to bed before the event).
With such a rhythmic shift of fire and oxygen, the effect of excitement and anticipation of new excitement is achieved, which is much more fun than constant excitement or constant anticipation.