Memory and the past are both positive and negative forces in Breakfast at Tiffany's. For some characters, memories are the only truly happy things they have in their lives since those recollections represent a simpler and safer time. But, in other instances, memories and the past simply won't let go of their hold on the characters' lives and those people are forced to face them again and again. These memories become harmful or sad when characters can't move past them or can't look beyond them to the hope of finding happiness in the present and in the future.
Breakfast at Tiffany's is an exercise in looking back. It's all about how the past sustains the characters.
The novel is about leaving the past behind and looking forward to better things in the future.