How is The Great Gatsby a satire?

It is satirical of 1920s America and culture. Everyone was selfish and only interested in money and extravagant things. The characters in The Great Gatsby are just the same. Everyone was only interested in big parties and spending money, Jay Gatsby throws big extravagant parties. Everything was a bit fake and hedonistic, just like the character of Daisy. Notice how she has an affair with Gatsby then leaves him at the drop of a hat at the end of the novel. Also, on the fake and selfish note, notice how many people go to Gatsby's parties, yet how few (1 party person, Owl-Eyes) actually attend his funeral.