From NY Times's obit on Tony Schwartz, the guy who created Lyndon Johnson's "Daisy Nuke" TV advert:
“The best political commercials are Rorschach patterns,” he wrote in his book “The Responsive Chord” (Anchor Press, 1973). “They do not tell the viewer anything. They surface his feelings and provide a context for him to express these feelings.”
This is really true of any of the best influence writing. Even business writing. When I am crafting a new case study, I take care in providing images that provoke emotions within my audience. This gets tricky if the audience is not homogeneous: having to write for labor leaders and managers isn't as hard as one would think (they really aren't that far apart) but you do need to stop and think about it.
I would argue that much of preaching follows this. You may not learn as much from this style, but it hits home and you remember it.
