The doctor starts checking down the list, "Dissatisfaction? Yes. Sad? Check. Suffering? You bet." The diagnosis: "You've got the blues." The musician in "The Weary Blues" sings "Got the Weary Blues, / And can't be satisfied– / I ain't happy no mo." The blues is all about expressing your pains. They can be emotional, physical, or financial, but the more you have the better the song. Or so it seems. Great blues musicians will not only try to sing as if they are in pain; they'll try to make their instruments sound the same too. This is why the piano is moaning throughout the poem.
The blues is an African American musical style, but the act of expressing suffering through art is found in many cultures.
An audience can't understand the singer's suffering if they haven't experienced it themselves.