You know that your happiness and suffering depend on the happiness and suffering of others. That insight helps you not to do wrong things that will bring suffering to yourself and to other people. If you try to help your father to suffer less, you have a chance to suffer less. If you are able to help your son suffer less, then you, as a father, will suffer less. Thanks to the realization that there is no separate self, you realize that happiness and suffering are not individual matters. You see the nature of interconnectedness and you know that to protect yourself you have to protect the human beings around you.
That is the goal of the practice—to realize non-self and interconnectedness. This is not just an idea or something you understand intellectually. You have to apply it to your daily life – Thich Nhat Hanh