Books
Guilt was the grease in which the wheels of the authority turned.
— Terry Pratchett · Small Gods

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Pratchett's line says authority runs on guilt, the way machinery runs on grease. Make people feel guilty and everything turns smoothly. It's a cynical joke about how institutions keep power moving without needing much force or fuss.
Context reviewed