Because those were the so-called Roaring Twenties. That was the period of extreme wealth, both in the sense of money, and art and culture. Those were the "crazy years", of industrial growth, changes in lifestyle and cure, and of course, the blossoming of jazz music. In that way, the spirit of the whole era was crazy for parties, and thus, Gatsby's parties exemplified exactly that.
Answer:
I can help with describing some archetypes and examples. I do not know about sources, but they shouldn't be too hard to find if you look them up.
Explanation:
Archetype: The Outcast
This character is banished for a crime against humanity.
EX: Shrek, Hagrid, Simba, Maleficent
Archetype: The Star-Crossed Lovers
Their love affair has disapproval of friends, family or society; it ends in tragedy.
EX: Romeo and Juliet
Archetype: Friendly Beast
The animal or beast keeps the hero company and joins the hero on his/her journey.
EX: Chewbacca, Dolby
