Is the message of "Fences" by August Wilson optimistic or pessimistic? Why?

The message of the play is guardedly optimistic. At the play's conclusion, Troy has died and his transgressions are forgiven. His brother Gabriel, whom Troy sent to an institution, plays the trumpet to herald Troy's admission into heaven. Gabriel's blowing of the horn shows that he has forgiven his brother and wishes for him to be remembered in a positive light. Troy's son Cory, from whom he was estranged, also forgives his father and attends his funeral. In addition, Rose, Troy's wife, has managed to keep her family intact, and she has raised Troy's daughter, Raynell, who was born to Troy's mistress, Alberta.

However, the end of the play also contains the breaking of Gabriel's trumpet mouthpiece. This symbolizes the way in which Troy's ascension to heaven is not as direct as Gabriel had wanted. However, Gabriel howls and dances instead, and Wilson suggests that through Gabriel's efforts, Troy will somehow enter heaven. Troy is not an angel, but the forgiveness of his loved ones shows that he has, in some ways, lived a blessed life. The play therefore ends on a hopeful note.

Is the message of "Fences" by August Wilson optimistic or pessimistic? Why?

The way the play ends seems optimistic to me. Where Troy was unable to mature enough emotionally to change and to avoid repeating history with his son, Cory is able to make that emotional step and take responsibility for his own development. 

The play, to me, is as optimistic as Cory's outcome, which is positive despite the challenges he faces. 

What does the title of the play "Fences" refer to? Is its message optimistic or pessimistic?

The "fences" referred to in the play's title have several meanings. Rose asks Troy to build a fence around her house, and Troy and Cory wonder why she wants to have her house fenced in as, Troy says, she has nothing anybody wants. For Rose, a fence is a measure of protection for her family, and her desire to build a fence signifies her desire to keep her family together. For her, a fence symbolizes togetherness.

However, the fence in the title also has other meanings. As Bono, Troy's friend, says, "Some people build fences to keep people out . . . and other people build fences to keep people in." Troy builds fences around himself and isolates himself. In his case, fences symbolize isolation and psychological distance. He kicks his son, Cory, out of the house, and tries to hide from his fears in the outside world by keeping himself behind a fence. One of his greatest fears is death, but death is able to get him anyway.

The play is both optimistic and pessimistic, in my opinion. While Troy fails to keep death at bay, the world is somewhat more welcoming of him than what he imagines. For example, he has been affected by racism but still manages to win the job of driving a garbage truck, formerly reserved only for white men. His victory may be small compared to the dreams he once had of playing major league baseball, but it is a victory nonetheless. And, in the end, Rose keeps some of her family together, including Raynell, the daughter of Troy's now-dead mistress, as Rose raises Raynell as her own child. You may have a different view.