What is the right balance between the setting/atmosphere of a novel and the dramatic elements?

In “Writing Fiction”, Janet Burroway speaks of a scene as being like an oyster. The atmosphere and setting of the scene makes up the meat of the oyster, and the dramatic elements make up the pearl. As any pearl diver knows, there needs to be a balance between oyster meat and pearl. If the pearl is a mere speck, too small to be seen with the naked eye, then the fisherman will cast the oyster back into the sea without having taken anything from it. The analogy works well for a scene. What can h...