We don’t always get what we want. Life doesn’t work that way. It’s one thing if you wish to win the lottery, and then don’t. With the odds stacked against you, you don’t expect to win anyway.
However, what if you put in for a promotion which you felt was your due reward for excellent work, and then the job goes to a colleague with less experience and a poor work ethic? You will be angry, possibly even quit to find work elsewhere.
Your character’s can’t get everything they want either.
Your ask is to write a story in which your character wants something but doesn’t get it. Remember that the readers need to experience the range of emotions that come with desire and disappointment.
Reread. Do emotions come through?
Have fun with this one.