The quote reflects on the nature of change and how time can solidify a person's character. It suggests that as we grow older, our experiences can lead to a fixed way of being, much like a shell that forms around a grain of sand. This process might be perceived differently by various people. What some see as a burden or irritation, others may view as a beautiful transformation.

In Jodi Picoult's "My Sister's Keeper," this idea highlights the duality in life’s experiences. Changes may be uncomfortable or challenging, but they can also result in something valuable and meaningful. It emphasizes the subjective nature of perception, where the same situation can evoke vastly different interpretations depending on one’s perspective.