There is a story about two brothers, one who is an optimist and always sees the positive side of things, while the other brother is a pessimist who thinks everything is difficult and bad. A psychologist suggests testing the brothers' personalities by giving the pessimist the best toys for his birthday while giving the optimist a box of dung. While the pessimist complains about the gifts he receives, the optimist is happy with the dung, believing that where there is dung there must be a horse.