People live for love. They kill for love. They die for love. They have songs, poems, novels, sculptures, paintings, myths, legends. It’s one of the most powerful brain systems on Earth for both great joy and great sorrow.

The quote frames love as a primary human force with extreme behavioral consequences: it can motivate altruism and beauty (songs, poems, art) as well as obsession, conflict, and self-destruction. By calling it “one of the most powerful brain systems,” Fisher shifts the discussion from sentimentality to biology, implying that love operates like a drive—compelling, sometimes irrational, and difficult to override. The catalogue of cultural forms underscores love’s universality and its role as a generator of meaning across societies. The final contrast—“great joy and great sorrow”—captures love’s dual nature: the same neural intensity that produces euphoria can also produce grief, jealousy, and despair.