Everyone wishes to have a happy life, including animals. But many are unhappy, and their unhappiness comes mainly from a causal relation of the mind. When we wish to own more material things, such desire will drive us to give more time and energy to fulfill that wish, resulting in bigger pressure, busier pace, less free time in life and eventually depriving us of any sense of happiness. Although the original intention of desire is to gain happiness for ourselves, it ends up destroying our happiness. Therefore, it is absolutely necessary to properly manage our desire.
~Depicted from THE HANDBOOK FOR LIFE JOURNEY - On The Three Poisons-How to Handle Desire