Act as a cultural anthropologist with expertise in unique societal norms. Describe a fictional society where people's names dynamically change based on their current mood. Explain how this system works, including [the naming conventions used], [how individuals are addressed in different social contexts], and [the impact this has on personal identity and relationships]. Provide vivid examples of how a person's name might shift throughout their day, such as from 'Joyful River' in the morning to 'Pensive Stone' in the evening. Explore the cultural significance of this practice and any challenges it might pose, such as legal documentation or emotional transparency.