In two famous Shakespeare tragedies, Hamlet and Romeo and Juliet, the Bard of Avon uses characters too blind to their own moral absolutism to demonstrate the importance of compromise. Indeed, because they are tragedies, the characters must necessarily be flawed in a fashion that causes them to make poor decisions. The results of those mistakes then form the basis for the tragedies.
Hamlet's plot is driven by a series of desires for revenge: King Hamlet's ghost telling Prince Hamlet to avenge his death as well as Laertes seeking to restore his honor after Polonius and Ophelia pass away. Both are unrelenting. When Hamlet offers his apologies to Laertes in Act V, Scene II, the latter refuses to take them, citing his own personal honor. More significantly, much of Scenes IV and V could have been avoided had Hamlet killed Claudius during "prayer." His choice not to do so on moral grounds prolonged the story and resulted in the deaths of Hamlet, Claudius, Gertrude, Laertes, Ophelia, and Polonius. Alternatively, Hamlet might have considered acting mad in certain contexts, but preserving some relationships that were important to him (i.e. Ophelia). Most of the plot events can be attributed to the uncompromising nature of these characters.
In Romeo and Juliet, the two lovers are too lovestruck to contemplate anything apart from a life together. The play ends with their unnecessary suicides as a way to illustrate the silliness of such unrelenting love. Surely Romeo and Juliet should love each other desperately, but it is not rational to believe that suicide is a helpful solution to their grief. Their inability to bear that pain -- in other words, to temporarily compromise their love for their own sake -- is what makes the play a tragedy. Not only do they die, but they die unnecessary deaths at the hands of absolutism.
All these if-onlys solely serve to heighten the sadness of Shakespeare's tragedies. We, as the readers wishing deeply for a happy ending, want the protagonists to take off their blinders and abandon their tunnel vision, but they cannot. This is human nature; I am far from convinced I could be any different. It is part of Shakespeare's critique of human nature as too stubborn, too arrogant, too foolish. These opportunities, missed because of obstinacy alone, serve to deepen the plot and reinforce the emotional poignancy of the text.