There was once a teacher who was walking together with his students around along the riverside. While walking they found a group of dogs laying down peacefully under a tree. One of his students remarked,"why can't humans live peacefully just as these dogs".
The wise teacher posed for a while and said, “That’s true, these dogs lie in peace, if I were to throw a bone there, the dogs won't be so peaceful anymore. They will start fighting for the bone. Humans are the same, as long as there is selfishness between two people of something, there will always be rivalry. If there is not greed for the same, the two will be best of friends.”
Only those who set small achievable goals and realize that one day they will depart from this world, leaving behind all worldly thinks can live a peaceful life.