Who has never experienced disappointment in their life? At least, almost everyone has been disappointed once in their life. The outline of the cause of disappointment is expectations that are not in line with expectations. The results are not worth the effort and estimates. The calculation was far off.
Working hard to be appreciated and seen with respect and admiration, the rewards are not appropriate. then try to give more attention to the person we like, but it turns out he returned it with a hurtful word. That's how disappointment works. That's why, many people are traumatized to hang their hopes up to the sky. Because the fall is very, very painful.
However, if investigated further, there is always a gap behind the expectations that do not match expectations. There are efforts that have not been maximized and there is also a destiny that wants to save us from danger. We don't have to respond to disappointment with regret.