Happiness is one of the most common feelings of human being. A wise man once said: “Life is an adventure of finding happiness”. The causes of it are varied, but in most cases can be clarified into three reasons. First, it appears that being able to do things as pleased is a major source of happiness. This depends on what kind of personalities different people have. An introvert can feel happy when reading a book under a tree while an extrovert enjoys playing with friends. This factor is so simple that it became hardly noticed when it is happening, as a result, people tend to remember it when it have already gone. For example, a mountain climber often thinks back of the days he sat with his family in front of the fire place; a soldier finds himself treasures a moment of silence before the battle. Second, people like to be praised, hence being rewarded is another cause of happiness. Because of the fact that getting rewarded means the hard work one did is recognized and approved, they get the feeling of worthy and optimistic thoughts about themselves. For instance, a moderate student easily bursts out laughing because he gets a B mark, and thinks he could do better next time. Once a person thinks that way, it is undeniable that he or she is indeed happy. The final factor of happiness is being loved. In view of love, there is a likelihood that the more beloved people are, the happier they become. The obvious explanation is being loved equals being important to someone, no matter who they are. Knowing that there are people in the world love and want someone to live happily, there is no reason for that person to feel unhappy. The causes of happiness are numerous, which leave one wondering why many people nowadays do not feel as happy as they should. Or is it simple that they do not realize what true happiness is?