On Mamet's Three Questions

In his book Bambi vs. Godzilla, David Mamet claims that all one needs to know about dramatic writing is contained in three questions:

Who wants what from whom?
What happens if they don't get it?
Why now?

The first two questions point to the four basic elements of drama: PROTAGONIST, ANTAGONIST, GOAL, and STAKES. These four elements are inextricably linked:

The PROTAGONIST pursues the GOAL. The ANTAGONIST tries to prevent the GOAL from being acheived. The STAKES are the negative consequences if the PROTAGONIST fails and the ANTAGONIST succeeds.

For your story (and every act, sequence and scene within said story), you need to know these four things.

The third question points to the causal progression between scenes that predominates dramatic writing. Each scene (following the Inciting Incident that starts the story proper) has its seeds in a previous scene, most often the one that directly precedes it. Moreover, the Inciting Incident itself, often has its seeds in the backstory of the PROTAGONIST.

This cause and effect relationship provides the momentum and tension that keep an audience enthralled in a story.

Three simple questions. But, as Mamet points out, these dramatic principles are easy to understand but can take a lifetime to master.