In the excerpt from Facing the Lion: Growing Up Maasai on the African Savanna, the author works so hard in school because he wants to become a doctor and help his people. He recognizes that many Maasai people suffer and die from preventable diseases, and he wants to make a difference by becoming a doctor and providing medical care to his community. He also believes that education is the key to achieving his dream and making a positive impact on his people's lives. Therefore, he works hard in school and studies diligently to achieve his goal of becoming a doctor.