In "Thanks for the Memories" by Cecelia Ahern, the narrative revolves around the complexities of human experience and the often hidden depths of personal stories. The main idea emphasizes that superficial appearances can be misleading, and true understanding requires deeper connection and empathy. People may project certain images, but their lives often hold unseen struggles and emotions.

The quote "You can't know everything by looking at me. You can never know by looking at someone" encapsulates this theme, highlighting that assumptions based on outward appearances fail to reveal the full reality of a person's life. Ahern encourages readers to look beyond the surface to appreciate the intricate stories that everyone carries within them.