shidou's philosophy is that every human is meant to leave their genes (impact) on the world whether its through their job, connections,, aspirations, kids, ect. to him, he leaves his mark with soccer. a goal is fertilization, and the joy that sparks from making that goal, that "explosion", is birth. he doesn't just have a desire for soccer, to him it's what hes been programmed to do. its living. he needs it like he needs to breathe plain and simple..