When Daisy and others travel to the city for the day, they are drinking mint Juleps in their hotel suite. Their glasses are filled with a bright green liquid, but mint Juleps are not bright green. True Juleps are Bourbon, water and sugar over ice with a spring of mint.
When Gastby first meets Daisy (Mira Sorvino), she is driving her car. She pulls up, chats to him and drives off, she then returns after going a little way up the road. She stops again and Gatsby gets in. Daisy once more drives off. During the whole scene, Sorvino doesn't appear to be at ease, driving, what to her is a vintage motor car.