McKay personifies America as a woman who feeds him "bread and bitterness" and who sinks her "tiger's tooth" into his throat. By using the pronouns she and her to refer to America, McKay turns the concept of a country into a person who can cause the narrator harm even while he loves her. The effect of this personification turns the relationship between the narrator and his country into a more personal relationship, full of the conflicting emotions that come along with loving a person.
Why believing in yourself is so important: A strong belief in yourself can bring you all these benefits and more: You recognise your ability to accomplish goals