1. Goose is a social animal: Goose is a social animal, and they are used to living in groups. Keeping a goose alone will make them feel lonely and anxious and affect their health and happiness.

2. Goose is a defensive animal: Goose is very possessive of territory, and they will take the initiative to protect their territory and partners. If only one goose is kept, it will think that the whole territory is its own, and outsiders may be aggressive when they enter.

3. Goose needs partner interaction: Goose will play and communicate with each other, which will help their psychological and social development. If there is only one goose, it will lack normal interaction with its companions, which is not good for its behavior and mental health.

4. Reproductive needs of geese: If only one goose is raised, the physiological and psychological needs of reproduction cannot be met. Geese usually build nests, hatch eggs and take care of goslings together, which is their unique reproductive behavior. Raising a goose alone can't meet these natural needs.