The Ghost of Krapp

I think Samuel Beckett describes Krapp eating bananas in the beginning of the play to show a similarity between the old Krapp speaking on the tape, who ate "three bananas and only with difficulty restrained a fourth." There are definitely similarities between the two Krapps, like the fact that they are lonely, sitting by themselves in the darkness. Neither will ever sing.
Despite the similarities, the current Krapp is more morose, the burnt ashes of what used to be somebody.

"Perhaps my best years are gone. When there was a chance of happiness. But I wouldn't want them back. Not with the fire in me now. No, I wouldn't want them back."

The 39 year-old Krapp still had a "fire" in him, and although he recognized, as the current Krapp also would, that the best might be behind him, Krapp at 39 was not a lost cause. He still had hope, because he did not regret the way things had turned out to be, and he did not want the "best years" back. I think the current Krapp would "want them back," because the "fire" that burnt inside Krapp 39 years ago burnt out long ago. As Krapp listens to himself 30 years ago, I think he is trying to start the fire back up, but he fails. Although Krapp used to be lonely, he was still somewhat optimistic on what could come later in his life. The old Krapp lived in the present, but the current Krapp has given up hope, and is literally living in the past, listening to old tapes of his life.