Why is November upset at the end of the story, and how does October cheer him up?

November is upset because he does not think his stories are as good as October's. He thinks that his are too dark. October reassures him that his are bound to be darker, since his nights are longer and he is not as warm. In other words, he should stop comparing himself to someone else and accept who he is. November understands this and says that no-one can help being who they are. This cheers him up.