Why do people suffer?

I can see not a few people who get suffered are those who like to focus a lot on themselves, say, they like to blame why untoward things would happen to them; they like to blame why others haven’t done this or that to them as they wish or demand; they like to blame why others don’t offer them as much love as they want, etc. Really, they can have a superpower to blame. In fact, what these kinds of people focus on are their own feelings, their own needs, and their own desires. When they know to live their lives beyond themselves by contributing to others, finding themselves smaller than others (forget about themselves even just for a minute), they will suffer less and less or even none.