Question: Why do they never show Mandy? They obviously did it on purpose.
Answer: Dupree wants an ideal fantasy woman, inspired by his enjoyment of Audrey Hepburn movies. Molly says that Mandy is a sl*t, but the larger issue is that Dupree needs to be more responsible and stable. I think Mandy was never shown because he never saw the real her. He was living in a fantasy world.
Answer: Most likely just to leave it up to your imagination.
Jason Riley