Music gives pleasure because your mind keeps predicting what comes next. Each correct prediction triggers dopamine. You can't make good predictions for unfamiliar music, so you don't get the dopamine. But when music is too familiar, something strange happens. You don't get the dopamine either because your brain predicts it effortlessly. To make you happy, music must be at the sweet spot of novelty and familiarity.
When a monkey loses a banana to a rival, he feels bad, but he doesn't expand the problem by thinking about it over and over. He looks for another banana. He ends up feeling rewarded rather than harmed. Humans use their extra neurons to construct theories about bananas and end up constructing pain.
A lizard never thinks something is wrong with the world, even as it watches its young get eaten alive. It doesn't tell itself "something is wrong with the world," because it doesn't have enough neurons to imagine the world being other than what it is. It doesn't expect a world in which there is no predators, so it doesn't condemn the world for falling short of expectations. it doesn't condemn itself for failing to keep its offspring alive. Humans expect more, and we do something about it. That's why we end up focused on our disappointments instead of saluting our accomplishments.