Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Though the content suggests the opposite of the tone, the attitude of the narrator toward the subject matter is one of disbelief that his time has been wasted in such a way. He’s annoyed that he has had to listen to such a stupid tale (about Dan'l Webster) from a man who seems to take it so seriously. His effort to reproduce Wheeler’s ungrammatical dialect feels slightly mocking.