The history of human beings is naturally a process to pursue happiness, which is the ultimate purpose of life. Happiness makes us cope with our careers energetically and harmonise life1. However, the word "pursue" evidences that happiness is like a horizon(地平线), when we move further, it2away.
Obviously, defining happiness has3mankind for thousands of years because individuals all have their own4and, more critically, human desires are almost limitless. 5is the common standard for happiness of merchants, yet their dreams of being billionaires and even zillionaires always follow the fulfilments of the dreams of being millionaires. The process of struggling for may-be happiness always ends in must-be6. Thus, the definition of happiness can hardly be7Nevertheless, although happiness is indefinable, it is still easy for us to find the8examples of happy people, who, in fact, share three features in common: optimistic mentality, 9body, and stable income. It is apparent that most of the sufferings are10by external surroundings and they are nearly unavoidable. Thus, one can only change his mentality to11them. Meanwhile, without health one cannot sustain happiness to enjoy the12of life.
Furthermore, to be realistic, a beggar, while struggling in poverty, can never be as peaceful as a millionaire13on the Pacific ocean. Hence, stable income is also significant for achieving happiness.
To summarise, to define happiness will not be so hard if humans can understand happiness in a standard way and eliminate(消灭) their14totally. However, before the realization of this15, being optimistic, healthy, and financially independent may be the "keys" to happiness.
