**3. Analysis of the effect on the happiness of Korean college students**

As academic interest in happiness increased from the 1960s, scholars' early attention focused on indicators, such as age, gender, ethnicity, income, residential density, and environmental pollution level as factors affecting happiness. However, sociodemographic variables have limitations in explaining the subjective happiness of individuals because the variance of these demographic factors to explain happiness is not very high, for about 15%, and happiness is subjectively experienced by an individual in life. Therefore, recently, studies on psychological factors that affect individual happiness have been actively conducted [11, 12].

In research on happiness, various terms like happiness have been dealt with depending on the researcher. "Subjective well-being" is a concept that reflects positive aspects as well as the absence of negative aspects. It is similar to the meaning of the reflected subjective well-being [12, 13].

As a sociodemographic factor affecting happiness, the degree of happiness was found to vary according to gender [14, 15]. Also, there are studies that economic level [16, 17], grade [18], etc., influence happiness. The level of happiness was different by health condition [15, 16] and by living area [17].

Korean young people go through a huge war for entrance exams and their quality of life is very low. According to data from Statistics Korea [4], the problem that 13–18-year-olds are most concerned about is "study and grades (46.5%)," indicating that academic stress is severe. Academic stress appears not only in Korea but also in all students living in Asian countries, such as Japan, Singapore, China, and Hong Kong, which have a culture that values achievement motivation highly. This phenomenon occurs because the amount of study is excessive and the expectations for academic results are high [19]. If this is because this period is ahead of the huge gateway of entrance exams for students, can college students who succeeded in entrance exams be relatively free from academic stress? If college students' academic stress is not properly managed, their confidence is lowered and ultimately acts as a factor that negatively affects their sense of well-being [16, 20].

Another factor influencing happiness is interpersonal skills. Interpersonal relationships are a basic human need, and since the satisfaction of life is improved through the satisfaction of these basic needs, smooth interpersonal relationships are viewed as a key element of happiness [21, 22]. Interpersonal ability refers to the comprehensive ability of an individual to develop relationships with other people in his or her life in various areas. Lee et al. [23] and Jung [16] studied where the sense of happiness experienced by college students really comes from. When considering the aspects of relationships and happiness comprehensively, it was confirmed that the relationship with others, that is, the sense of bonding, is a factor that promotes happiness. Kwon [24] stated that college students had a high sense of self-efficacy in school life and friendly relationship with the state and that the higher the emotional support from the people around them, the higher the degree of feeling of happiness. From the above studies, being able to learn how to be interested in and relate to others plays an important role in being happy. In Lee's study [12], "Strive for Relationships" is mentioned as a factor of college students to be happy and real response of a student is as below:

*I cannot be happy alone. If life becomes meaningful and I am remembered as a precious being to others more than 'I am precious to me,' I think it will contribute to a successful and happy life. To do that, you need to form an amicable, prudent, and sincere human relationship (a student).*

As a result of the study on the relationship structure between personality and happiness, there was a very close correlation between the relationship between personality and happiness. Among the sub-factors of the five personality factors, sincerity, openness, extraversion, and affinity were particularly closely correlated with happiness, and neuroticism was found to have a negative correlation [25]. Jun & Shin [5] investigated the influence of five personality factors (initiative, depression, consideration, accuracy, and judgment), which showed that depression is the most influencing factor that impacts negatively on the college students' happiness, and initiative and consideration positively affect the happiness of college students. They used data from 5283 university students among 8485 data from the third year of the Korean Education & Employment Panel (KEEP) II [26] provided by the Korea Vocational Training Institute. In addition to personality factors, the study shows that self-understanding and self-efficacy are important factors affecting college students' happiness.

Park & Lee [25] also gave the results that belief about one's abilities affect happiness. The results of this study show that to enhance the happiness of college students, analyzing, understanding, and evaluating positively our personalities make our lives with more happiness. Many studies on happiness have revealed that there is a positive correlation between happiness and self-esteem [27, 28]. It has been shown that optimism influences happiness by directing one's behavior and life direction in a positive direction. Lee [12] analyzed the students' essays about how to try to be happy college students and the first category is "self-satisfaction and positive thinking."
