The study of disappointment is just in its infancy, but there is a definite physiological aspect to what happens in the brain, when people experience the emotion we call “disappointment.”
To the layman, it seems so obvious that…
When someone considers a risky action, he or she will form a prior expectation of the payoff, and if the outcome is worse than expected, that person will experience an emotion called disappointment. If the outcome exceeds expectation, the emotion is called elation.
Psychology of Disappointment Infographic
Source: Best Psychology Degrees