According to the author at the beginning of Chapter 21, what makes a narration or story truly effective and worthwhile?

At the start of Chapter 21, the author outlines his philosophy on effective storytelling, emphasizing that a narration's value is measured by its emotional impact on the audience. He states that a speaker's words are considered futile if the listener is not deeply moved. A successful narration is one that causes the listener to "sway upon hearing them," makes the "hair on the body stand on end," chokes the throat with emotion, and brings "tears of love and joy" to the eyes. According to the principles laid out in Chapter 21, any story that fails to delight the listeners and evoke such a profound, physical, and emotional response has ultimately gone in vain. This sets a high standard for the sacred stories of Sai Baba that are to follow.