Gatsby is trapped in the past, and Daisy is entrenched in her present. Why is this problematic?

Gatsby's life is an illusion. He pretends the five years he was away as non existent. His love for Daisy is obsessive. I think he is in love with the idea he has built up of Daisy rather than Daisy herself. For Daisy's part, she is entrenched in Tom's money. She cannot see past the wealth and sad life she has created for herself. She can never be the illusion that Gatsby has made of her.