Final answer:
The character in question is likely Phoebe Caulfield from 'The Catcher in the Rye,' a character who is described as smart and challenges Holden's negative view of life.
Step-by-step explanation:
The character that matches the description of being a "genius," "neat," and "polite," and who confronts Holden with the statement, "you don't like anything," is likely referring to a character from J.D. Salinger's novel The Catcher in the Rye. In the novel, Holden Caulfield is often cynical and pessimistic about life.
The character that challenges his worldview could be Phoebe, his younger sister, who is not only smart and caring, but also provides a stark contrast to Holden's often negative outlook on life. Phoebe's innocence and straightforwardness force Holden to confront his own complexities and discontent.