Nick makes a number of observations about Gatsby's party-goers in Chapter 3. He describes them like moths (thoughtless) flocking to the bright lights of Gatsby's house. Nick also notes that many of the people don't know each other and most of the guests don't know or have never met Gatsby:
I believe that on the first night I went to Gatsby’s house I was one of the few guests who had actually been invited. People were not invited—they went there.
The guests treat Gatsby's house like it is an amusement park. Jordan and some acquaintances discuss Gatsby and it is clear the only thing they know about him are rumors about his past. Toward the end of the night, Nick notes that many people were drunk and some were beginning to argue.
When Owl Eyes, who admitted to being drunk for a week, emerges from the wrecked car, he claims that he isn't a good driver and that he wasn't even trying. Then he claims that he was not driving the car. The driver is so drunk he doesn't know why the car was even stopped. The driver is simply an irresponsible man who drank too much and tried to drive. His obliviousness to the significance of his own actions and to the world around him captures the general attitudes of Gatsby's party "guests." Most of the guests don't know Gatsby. They use his house to party and to serve as a high society spectacle of social gathering; they do it for notoriety. The fact that most of them do not know Gatsby, let alone each other, reveals that the social interactions and relationships formed at these parties are all in good fun, but are trivial and superficial.