Samuel had to buy three tickets for Natasha, Peter, and Patricia to come to the play. He bought Chinese takeout, and they ate at the kitchen table, something they never did. Patricia was silent. After dinner, Samuel held up an envelope and asked his family to come see him as the lead in A Raisin in the Sun. He handed everyone a ticket and looked happy for the first time in a long time. Natasha thinks that seeing her parents' flaws was like losing her religion, and she no longer believes in God or her dad.
As far as Samuel is concerned, A Raisin in the Sun is a very literal representation of all his hopes and dreams for his life. He is, essentially, influenced by the history encapsulated in the play—history that still affects Samuel as a black man in New York City half a century after the play was written.
Patricia called Samuel foolish and then walked to the bathroom and slammed the door. Later, she refused to go to the show. Peter and Natasha sat in the front row, and Natasha wished that she could say her dad's performance was mediocre—it'd explain the years of rejection if he'd been a poor actor. His performance was breathtaking.
Patricia is far too unwilling to trust Samuel with anything to acknowledge that this is something big for him, which shows that one can use isolation (both of oneself and of another) as punishment.