Vague and constant desire

From Towse comes a new word to me: saudade, which has a marvellous painful, tragic quality: "a feeling of longing for something that one is fond of, which is gone, but might return in a distant future. It often carries a fatalist tone and a repressed knowledge that the object of longing might really never return". How could I ever have got this far in life without discovering such an essential word sooner?