The 1920s was also full of corruption and crime. Due to the prohibition, illegal speakeasies and bootleggers became popular. In The Great Gatsby, the character Meyer Wolfsheim is based on Arnold Rothstein, a famous gangster that is speculated to have fixed the World Series in 1919.
The novel also highlights the immorality of the characters, especially regarding adultery. Every character has either cheated on their spouse or have encouraged it. Gatsby is indifferent about Daisy being married and still attempts to pursue her. Nick Carraway and Jordan Baker both help bring Gatsby and Daisy together. Tom Buchanan cheated on his wife with multiple women.