Word of the Day... idee fixe

This is what happens to me sometimes when I’m writing a story….

idee fixe \ee-day-FEEKS\, noun:

An idea that dominates the mind; a fixed idea; an obsession.

The reality of obsession -- its incessant return to the same few themes, scenarios and questions; its meticulous examination and re-examination of banal minutiae for hidden meanings that simply aren't there; the cancerous way an idee fixe usurps other, more interesting thoughts -- is that it is confining, not rebellious, and not fascinating but maddeningly dull.
-- Laura Miller, "The Streetwalkers of San Francisco", New York Times, August 20, 2000

It became an idee fixe that he stubbornly adhered to in spite of the plain evidence . . . that obviously contradicts it.
-- Edwin G. Pulleyblank, "Prosody or pharyngealization in old Chinese?", The Journal of the American Oriental Society, January 12, 1996

Getting back to the idee fixe, let me say that it's what produces strong men and madmen.
-- Joaquim Maria Machado de Assis, The Posthumous Memoirs of Brás Cubas (translated by Gregory Rabassa)

Idee fixe is from the French idée, "idea" + fixe, "fixed."