Swantratatagami ji, you have a good heart that's why you think of those people. Life is miserable, not only their but ours as well. As compare to you they are more miserable, that is it. I think we all are individual, each individual is sum total of his/hers Karma (mental volition). Karma is mental action, and every mental action is translated into result. This is the theory of Karma. We all have different mental volition that is why we all are different. Buddha was asked this question. He was asked that why people were so diverse. He answered like this: कम्मसका माणब सत्ता कम्म दायादा कम्मयोनि कम्म बन्धु कम्म पतिसरणम। कम्मं सत्ते बिभजती यदा हिन पणितताया ति। Karma is the cause, Being is descendant of Karma, born with Karma, Karma is his friend, Karma is his refuge and it is Karma which divides beings into superior and inferior. I hope you will find your answer inside this if not please don't hesitate to ask again.