Prayer might prevent you from getting what you want.

If Rambam is right about Divine Providence it is only available for those who have True ideas about God. If he's right about God, nothing we can do can change him. Therefore, this popular notion that our prayers can compel God to do something is not only a false idea, but also, ironically, likely to PREVENT us from getting the thing we want as believing it works disqualifies us from receiving divine providence.