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.

Source: "Why We Love, Why We Cheat." TED2006. Feb. 2006. Conference Presentation. Additional Information: This quote, from anthropologist Helen Fisher's 2006 TED Talk on the biology of love, is about the power of romantic love. Says Fisher, love is a function of the brain so powerful that it gives people a reason to live or die, inspires great art and literature, and causes both elation and despair; some people even commit murder in the name of love. Watch the full TED Talk here: Helen Fisher - Why We Love, Why We Cheat