Writers conceal mundane sources like small ads because they seem too obvious.

Evidence

Who owns stories and where do they come from? The last part of the question is one that readers ask all the time; writers are very poor at giving the answer. We don’t like to say “from the personal columns,” or “from the small ads,” even if it’s true. It sounds too obvious, too much like the way people assume authors operate. — Hilary Mantel, A Memoir of My Former Self- A Life in…, 35

Categorization

• XREF: XREF writes about how fiction writers mistake raw observational scraps for the true origin of their creations.
• SEED: SEED writes an essay on the trivial, unglamorous origins of major literary works.
• corroborated: 2 independent passages support this claim — Hilary Mantel, A Memoir of My Former Self- A Life in…, 35