The biggest problem of a person who has no difficulty in ensuring his own happiness is this: The unhappiness of others! Because it is very difficult to maintain happiness among unhappiness!
Not the world but the world you have created within the world determines the degree of your happiness or unhappiness!
Life has a tendency to provide a person with what they need in order to grow. Our beliefs, what we value in life, provide the roadmap for the type of life that we experience. A period of personal unhappiness reveals that our values are misplaced and we are on the wrong path. Unless a person changes their values and ideas, they will continue to experience discontentment.