The moments I thirst for when reading are the quiet ones. They tend to sneak up on the reader, no matter the forewarning they are given.
It's very much like looking over your shoulder or a sense of danger is coming… of something in the air. This feeling before the storm is a promise.
You feel a storm on the horizon and expect there to be one in the future. This is a promise that all readers take up with the author. By reading they are promised a payoff to the story and the emotions they want to feel. It is a horrible thing to break a promise between reader and author.
By delivering on your promises with a satisfying payoff, you keep the reader invested. An invested reader will go wherever you steer the story because they know that you fulfill the promises you made. They hope to witness moments of tension, action, grief, joy, and justice.
Readers expect a lot from a story if it is full of promises. By making promises for your story it becomes something grand in the reader's eyes. However, if these payoffs fall flat and don't reach up to the hype that readers envisioned. Then trust is lost and the story can never be the same.
The most important thing an author can do is set up promises, keep the reader invested, and fulfill these payoffs to create a story that grabs the reader's attention.