Most of us think that we are miserable because we don't have everything we ever wanted. Because we are not smart enough, talented enough, successful enough. Because we don't have enough money, etc.
You think that successful people are happy. Actually, the more successful someone is the less happy they become.
When you are poor and all your efforts are about providing yourself and your family with what you need... you have little thought about the inner emptiness... who cares, as long as you can fill your stomach.
But once you fulfill the base layers of Maslow's hierarchy, the yearning for inner peace, inner riches starts to become strong, loud, and misery creating.