Undeniable Rights of The Universe

Sometimes, life is bright and wonderful. Sometimes it's not, and when this is the case, we forget the light and shrivel up into human raisins of sadness. Why can't we find joy in all things and all circumstances? I've been thinking a lot about joy and contentment, their opposites, and their crucial role in our small but potent lifetime. Why aren't humans granted joy and contentment as undeniable rights of the universe? Why are both of these things elusive, and why must we put in so much effort to attain them? The simple answer, the easy answer that allows our brains a trivial and short-lived victory, is that we must work harder in order to attain these things, and that hard work causes us to live a fuller life. But what is a full life? Is any life lived not a "full" life? What makes it full? It became, it was, and then it ended. If joy and contentment were undeniable gifts to the human race, would we not consider every life a full one? In my understanding, the point of striving for a full life is to achieve a state of peace and lack of regrets about your life. But, if people were joyful to begin with, every moment would hold the significance necessary to generate contentment, and if we were naturally content, there would be no greed, no depression, maybe even no crime or broken families.  People would give freely of what they had, because they wouldn't be counting it and locking it in boxes they never open. Those who received it would feel blessed and thankful, because it was a gift they did not feel entitled to, given by someone who did not give it out of guilt, but out of joy. What would the world as a whole look like? I can't even imagine. Unfortunately, the chances of us experiencing this are not great. However, I am challenging myself to consider joy and contentment my undeniable rights as a human being, and whenever I am feeling dejected or greedy, I will polish the dust off these rights, reminding myself that they are mine if only I chose to use them, and exercise them to their fullest potential of the moment.