A Raisin in the Sun has a realistic and harsh tone, with the characters in the play not afraid to say what they mean when they mean it. The tone shifts depending on the character and the focus, with triumphant highs (such as the end of the novel, when Walter reverses course and the family commits to moving) and depressing lows (like when Ruth and Walter fight over Ruth's pregnancy).
The play’s central through-line of hope creates an optimistic tone, and while different characters at different points in the play condemn or endorse each other’s dreams, the play returns to that optimistic tone again and again. The characters are deeply aware of the inequity of the world around them—an inequity that directly impacts their lives. To that end, this sense of injustice can't help but infect the tone; in an unfair world, frustration is ever-present. Nevertheless, the novel ends on a note of love and support, the family taking one step forward towards their collective dream of mutual prosperity. The play ultimately ends on a bittersweet note through the fulfillment of Big Walter's dream to have a home for the family while the younger Walter is supported through his mistake.