According to Nancy Duarte's TedX Talk, what should every presentation have at the end? Why is this important?

According to Nancy Duarte's TedX Talk, every presentation should end with a call to action. The world must be described as a new bliss by showing the audience why they should adopt or accept your ideas. It is important because the presentation will be effective, impactful and well-remembered if it was ended in a poetic and dramatic way.