Zeus had a vision that the son of the nymph Thetis would be greater than his father. Obviously, he was making sure she married a mortal. Thus Achilles was born into greatness. When asked if he would rather have a long life of comfort or a short life of glory, it wasn't a choice at all. He was born to kill. His skill in battle was so great that even those who hated him were forced to admit that they could not win without him. Surprisingly, he also loved with the same intensity. Although the precise nature of their relationship is open to debate, Achilles' love for Patroclus is one of his defining characteristics, whether brotherly or romantic. His love for his mother is also evident, and this is probably the source of his irritability. It's funny to think about the extreme, brooding self-pity of an epic hero, but it perfectly illustrates his overall "greatness." Even their sneakiness and whining to their mother is great. Of course, we cannot talk about Achilles without mentioning his great anger, sung from the first verse of his epic.