1, family background: Matsuzaka Sugar grew up in a poor family, her father was alcoholic and violent at home, her mother was cold and uncaring to her, Matsuzaka Sugar grew up with a lack of love and security, which made Matsuzaka Sugar become very sensitive and fragile to human relationships.

2. Friendship: Sugar's friend Nanjo Aino is her only spiritual support, but Aino alienates Matsuzaka Sugar for some reasons, making Matsuzaka Sugar feel very lonely and helpless. The breakdown of friendship makes Matsuzaka Sugar skeptical of human relationships again, aggravating Matsuzaka Sugar's psychological burden.