In this example it all boils down to the example of a three-act paradigm:
I think this was a good way to attack the concept on how to build a mix/set. I've seen alot of DJ's playing sets without having a "story". Just the same type of tracks all night long. I really like the lines they draw to movies in this article where you have plots, highs and lows. This is also the key to creating a dynamic mix / set.
Your sets should be a journey through music... Not just a cheep ride with an old uncle.