This might be because the protagonist of the novel had a very important position in the plot, which made the readers have a strong emotional resonance. Or perhaps it was because the protagonist's personality traits, appearance, experience, character setting, and other factors left a deep impression on the readers. No matter what the reason was, this feeling indicated that the reader had developed a strong emotional dependence on the protagonist, and could even be said to be emotionally invested. This might be one of the reasons why readers liked this novel.