Plot might seem to be a matter of choice. It is not. The particular plot is something the novelist is driven to. It is what is left after the whittling-away of alternatives. The novelist is confronted, at a moment (or at what appears to be the moment: actually its extension may be indefinite), by the impossibility of saying what is to be said any other way.
He is forced towards his plot. By what? By the “what is to be said.” What is “what is to be said”? A mass of subjective matter that has accumulated—impressions received, feelings about experience, distorted results of ordinary observation, and something else—x. This matter is extra matter. It is superfluous to the non-writing life of the writer. It is luggage left in the hall between two journeys, as opposed to the perpetual furniture of rooms. It is destined to be elsewhere. It cannot move until its destination is known. Plot is the knowing of destination.
From Elizabeth Bowen, “Notes on Writing a Novel” in Pictures and Conversations (1975).