Both you and your group members are right. On the one hand, you don’t want to write a story that’s predictable. If the reader knows Lisa is going to accept the necklace from her new boyfriend, even though she knows he stole it from her own sister, then what’s the point of reading the story? But if Lisa is a generally honest person who is trying to forgive her sister for moving in with the man Lisa thought she would marry, that makes things more interesting. Will Lisa be able to forgive her one and only sibling, the person she’s always turned to in times of need? Or will this betrayal be impossible to overcome? Will Lisa’s new rogue boyfriend be just the revenge she needs? When Lisa is on the fence, so to speak, things are much more interesting and good writers know this.

In F. Scott Fitzgerald’s The Great Gatsby, the reader doesn’t know if Gatsby will reclaim his true love, Daisy, until the very end of the novel. In Raymond Carver’s short story “So Much Water So Close to Home,” the very last line of the story reveals whether Claire will come to terms with the fact that her husband and his friends found a dead woman’s body on a fishing trip and waited several days—until near the end of their trip—to report it. The characters waffle. Situations shift. And readers are eagerly flipping pages to find out what will happen because more than one option seems possible and plausible.

A pleasing moment of surprise is not, however, a moment that comes “out of the blue.” Writers have to lay the groundwork. In Carver’s “So Much Water So Close to Home,” Claire is more fragile; the one in the relationship who seems to follow rather than lead. Yet, partway through the story, she slaps her husband, Stuart. But here’s what came before: She is haunted by Stuart’s choice to continue with his fishing trip, rather than walk five miles to the car on opening day to find a phone and report the body. She imagines being in the river, face down, like the young woman who was found. And she questions Stuart: “It isn’t true . . . You didn’t leave her there like that?” Stuart and Claire’s relationship also has undercurrents of aggression. Stuart tries to bully her into dropping the subject. And earlier, before the slap, Claire sweeps her arm across the drain board in anger and frustration, crashing all the dishes to the floor. The slap is a surprise, but it’s not “out of the blue.” It is apparent that Claire is capable of such an action given what has come before.

So while surprise is an important element of fiction, your job is to make sure it follows as an organic outcropping of what came before. It all comes down to well-chosen details and the way they work together to show exactly what a character is capable of doing