Immortality is to live forever, watching decades and centuries blow over like dust in the wind, to watch cities and civilizations rise to their peak only to slowly whither away to the vast emptiness of time only to confound and amaze the generations yet unborn.
For a being like man who is born in time to escape its clutches and choose the t he or she wishes to leave this plan of existence is something worthy of envy. It could just be the greatest gift if it didn't come with such a heavy price to pay.
Long life is all man can actually handle. Immortality is to savor your meal till it spoils in your very mouth. If a man were to live for a 1000yrs, his mind may break long before he finds his end. He might outlive his humanity, afraid to make meaningful connections lest he watches them die. Life with love and all is no longer life but existence.
Then again, if you could gain his cursed gift for yourself or for someone, how do you think it will play out, even after a thousand years had passed Will you still be thesame or like a mirror fall and break a thousand times over.