Confronting one's reflection can often be a disappointing experience, despite the body being generally acceptable and functional. The physical appearance, which is seen as neatly maintained and slightly aged, doesn't fully represent the inner qualities and personality that truly define a person.
As Zoë Heller reflects in her book, the external image may be just a surface, while the real essence remains hidden inside. The outward self may not do justice to the depth and complexity of one's internal world, leading to a sense of disconnect and unfulfillment.