One could argue that the effects of culture and society completely steer the plot of The KiteRunner. The protagonist, Amir, grows up with another boy named Hassan, but they are from different ethnic groups, religions, and therefore, social statuses. These differences tear them apart and bring about the tragedies of the novel.
First of all, Hassan is discriminated against and bullied because he is Hazara, an ethnic minority looked down upon by the majority Pashtuns. Amir even finds a chapter in an old textbook that describes how Pashtuns tried to rid Afghanistan of Hazaras. In the story of Amir and Hassan's childhood, it is Assef, the neighborhood bully, who voices this opinion when he says he wants to make Afghanistan purely the land of Pashtuns. Amir fails to defend his friend against Assef's attacks, instead feeling ashamed that he spends time with Hassan. Assef's attitude toward Hazaras also leads to his assault of Hassan after the kite tournament which, along with Amir's inability to help Hassan and his decision to instead run away, drives the tragic plot of the novel. After the assault, Amir's guilt and shame lead him to find a way to rid the household of Hassan and his father, Ali. This means that when Amir and his own father, Baba, flee a violent and turbulent Afghanistan, Ali and Hassan stay behind. Later, Ali will be killed by a mine explosion, and Hassan will be murdered by the Taliban.
Culture and society also contribute to Baba and Amir's life in America. Baba was wealthy and influential in Afghanistan but must start completely over with menial jobs in California. He works hard to ensure Amir gets an education and makes the most of his opportunities. However, Baba finds it difficult to adjust to the American way of life, while Amir likes that the nation gives him a chance to start over and (he thinks) leave his guilt and memories behind. This, of course, ends up not being true.
In America, though, Afghani cultural expectations follow our characters. Amir's eventual wife, Soraya, is victim of a cultural double standard when she is somewhat ostracized for living with a man who was not her husband. She expects that it will bother Amir, and though he admits it does a bit, he still wants to marry her. This is an example of Afghani cultural values combining with a more American perspective.
Later in the novel, when Amir returns to Afghanistan, we see how the Taliban has changed the culture of Afghanistan since Amir and Hassan were children. People live under a much stricter rule, and Kabul seems to be falling apart. There are very strict rules on women's behavior, and the Taliban abuses and kills people at will. Amir witnesses the public stoning of an adulterous couple during the halftime of a soccer match, which showcases the fundamentalist beliefs of the Taliban. The disorder in Kabul also makes it difficult for Amir to adopt Sohrab (Hassan's son) when he...
decides to do so because there is no formal death record of Sohrab's parents.
The Kite Runner is the story of one man's redemption journey, but it is also the story of how cultural attitudes and differences in culture, ethnicity, and social status can result in tragedy. Hosseini has also said that he hopes readers get a better idea of how life in Afghanistan has deteriorated and how difficult the path can be for those who want to escape its turmoil.