In cinema, you tell the audience where to look. Every scene is constructed to say “Look here! this is what’s important.”
When you construct a message, you always design for both what you say and how you say it.
Use your emphasis hierarchy to clearly show the most important idea at every moment of your communication.
Indicate your emphasis with direct techniques: color, size, position, contrast.
How does surprise work in suspense movies? The director purposely manipulates the audience to pay attention to the wrong thing, and then surprises them with a sudden switch.
A clear emphasis hierarchy eliminates the chance your design will become an accidental horror show.
Story is the art of articulating emphasis. This is important; that is important. Now this. Now that.