Everyone shows up to the party, even people who were not invited. Most of the people don't even know who Gatsby is and how he looks like.
After the parties, people leave recklessly. There is a scene of a guy, called Owl Eyes, who crashes his car just a few seconds after he starts driving away. Furthermore, because he's drunk, he continues to drive it even after one of the wheels has come off.
"there is a last sweet and kind,
was never face so pleased my mind
I did but see her passing by
and yet I love her till I die