Happiness is considered the final good because it is the supreme goal of humankind. Humans do not choose happiness as a tool to reach another purpose but choose other things to achieve happiness. For example, people aim to earn more money, but it is not their final goal. They make money for the sake of something, better food, and a better house.
They seek such things to be happy, but they do not want happiness to obtain more financial means. Without happiness, any other means does not present any sense and lacks purpose. Thus, it contributes to happiness being a final point that people pursue in their lives. It is a self-sufficient term to which people strive and which people seek through different actions. Happiness is something individual for each person, however, happiness is the supreme good for all people.