As with much of the rest of the novel, Nick is a complete outsider at Gatsby's party. He is not from the same class or even from the same area of the country as the other party goers. Furthermore, Nick is one of the very few guests in attendance that is actually directly invited to the party, meaning that Gatsby has taken an interest in him.
Gatsby throws these parties merely to flaunt, and most of his guests never even see him, much less make his acquaintance. They are merely there to revel and become intoxicated. However, Nick has no interest in becoming drunk. Instead, he actively seeks out Gatsby. In keeping with his courteous way, Nick wishes to find the host of the party and thank him.
