In John Steinbeck's "East of Eden," the theme of disappointment stemming from unfulfilled wishes is prominently explored. The quote, "Wishing just brought earned disappointment," reflects the idea that longing for something without taking action can lead to feelings of unfulfillment and sorrow. Characters who wish for a better life or different circumstances often find themselves facing harsh realities instead of the dreams they envisioned.

This insight suggests that mere wishing is insufficient; it highlights the importance of effort and initiative in achieving one's goals. Steinbeck illustrates that while hope can be a motivating force, relying solely on wishes may result in deeper dissatisfaction, urging readers to confront their realities and take steps towards their aspirations.