You don’t write because you want to say something; you write because you’ve got something to say.

The line draws a sharp distinction between writing as mere self-expression and writing as communication. Fitzgerald’s formulation suggests that the impulse to write should come from an inner pressure—an idea, story, or insight that demands articulation—rather than from a vague desire to perform the role of “writer” or to speak for its own sake. It implies craft and purpose: the writer’s task is to shape something already felt or known into language that can be shared. As advice, it also functions as a test of seriousness: if there is nothing urgent to convey, the work risks becoming empty rhetoric or imitation rather than lived, specific meaning.