I think it is important to note here that while it is good and important to express what it is you want, that is not necessarily what it is you need. This concept will often arise when someone is the more Dominant partner in a relationship such as a parent. Those of us who have experienced the parental joys know well the cries of our loved ones all about what it is they want while having to be deeply conscious of what it is they need. The same is true in an adult D/s relationship. The more submissive member of the partnership can and should express their wants and perceived needs but it is up to the Dominant partner to decide their actual needs and if their wants can be granted as rewards.
So we struggle, because there is no actual other person there who will do that for us, the Dominant ones. We do have our wants, as silly and juvenile as they may be and we must decide, from a place of knowledge, self respect, and introspection. But also from a place of faith. Faith that this benevolent universe will also know, and present, to the open mind and knowledgeable eye, what it is we need. Even if it is not what we want. Hold your hand open, and have the strength to take the gift, even if it comes from a Panther.