Most people enjoy having some sense of direction when they embark upon their reading. They want to know where the author might be leading them. They want to know what landmarks they can hope to view. They want some predictability.
Predictability doesn’t mean boring; far from it. John Zorn’s piece, “Saigon Pickup,” is predictably unpredictable. One listens to the piece all the while waiting for that unpredictability. The listener who understands Zorn’s ideas concerning his music also understands that seeming unpredictability is one way of realizing those ideas. The listener expects to hear sudden shifts from one style of music to another. The listener might be jarred by some of those transitions, but the listener is willing and ready to experience them.
Similarly, predictability in writing doesn’t mean boring writing. Predictability simply is a way to let readers know what to expect. A writer can and should outline those expectations in the opening paragraph or a “start here” or “about” page. At the very least, the writer should indicate what is to follow. Some readers may appreciate a Dada-influenced piece, but, on the whole, most readers expect a composition to follow the normal patterns of writing. They have grown accustomed to being introduced to a main idea in the opening paragraph, to having that idea more fully explored in the body of the work, and to reaching some sort of conclusion regarding that idea in the final paragraph.
Predictability can be more nuanced; for instance, a reader familiar with Redhead Writing expects a certain tone and language. Without those things, Redhead Writing no longer is Redhead Writing. Readers would wonder what had happened to the irreverent voice and foul language. Readers find that voice and language predictable. They expect and need those things. Those things ground the reading experience. They tell the reader where he or she is and what to expect or not to expect.
Predictability, then, has nothing to do with worn-out or boring copy. It merely is a roadmap for the reader. It creates expectations and fulfills them. It tells readers what to expect, whether that be via an introductory paragraph or a writing style that embraces sarcasm and blue language.