Buddha said that all suffering comes from attachments.
If your focus is “I can’t be happy until such a desire is fulfilled” then, you won’t be. You are believing that your happiness depends on this one thing.
When you are attached your only thought is for this one thing that you haven’t got so you don’t see all that you do have.
When we are attached to some desire we repel it because our energy is taken up with the “not having”.
The key is to have preferences but not attachments – to ask for what you want and take action to bring it to you but continue to live fully.