How can we describe the society in which they live from the party in Chapter 3?
The Jazz Age is presented in chapter three of The Great Gatsby as an age of luxury, opulence (abundant wealth), and hedonism (love of pleasure).
The illegal liquor flows, guests come from everywhere and stay all night, cars are everywhere, the band is many-membered, Gatsby's house is turned into almost a carnival, the library is full of books that are unreadable (the pages are uncut--they are just for show), drunks drive, and recklessness abounds.
And the people thrive on rumors: about Gatsby's business, his war experience, and his past.
Gatsby does not take part in any of this, but at the same time, he is responsible for it all. He does not drink the illegal liquor, but he serves it.
In short, the society in general is irresponsible and shallow.
The first thing I would say is that this shows that their society is very interested in having fun. They are all eager to come to this party and live it up.
A second thing we can see here is that there is a difference in class between the people from East Egg and those from West Egg. The people from East Egg have been rich for a long time. The people from West Egg, like Gatsby, are upstarts. They have less refined manners, they don't know how to act in high society. The people of the two towns are in some amount of tension because of this.