The Spirit of a person lives in the Heart during the day. The Heart is in charge of joy, so a healthy Spirit brings brightness to a person’s demeanor. Liver is in charge of emotions, most specifically, anger. The Spirit also lives in the Liver at night. So, experiences perceived by the Liver are expressed as the Self in the Heart. If the Liver is injured (emotionally), it can attack the Heart. If attacked, the sense of Self can become damaged. In Traditional Chinese Medicine, sadness has the ability to heal the Liver. Then, the Heart can feel joy again. And the Spirit can rest.