How did positive thinking and self-confirmation helped me?
Have you ever noticed that sometime we talk to ourselves or dwell on some ideas for a period of time? Especiallly when we need to choose the best alternative among many options or make important decisioins, we will say or think inwardedly "I can do it" or " No, I can't do it, it's not for me." These talking and thinking are self-confirmtions which can affect the outcomes whatever you are doing or whatever you are going to do in a positive or a negative way.
Whatever you think can become true
I was grown up in a big family with eight children, four boys and four girls in mainland of China, and experienced unprecedented cultural revolution there. This well-known period from 1966 to 1976 in Chinese history spaned almonst all my school years from elementary to high school, I didn't learn much because we had to participate in all kinds of activities related to so-called revolutionary movement. What we were doing in school was to learn singing, dancing to praise Chairman Mao's great achievements, and learn to read, to write, and to recite Mao's quotes, and spread his words to househoods in the community. Because of the fact that my grandfather was classified as landlord when Chairman Mao established the new China in 1949, My grandfather was severely criticized and we, as decendents of a landlord who "exploited " people, were deprived of all the rights to participate in any social activities.
When one of my elder brother who is two years older than I and I need to go to high school in the same school year, we were told that only one of us was allowed to go due to the current policy that stipulated that only one child of each family of landlord or the like was allowed to attend high school in one school year. No matter how good our grades were, we were not allowed to attend high school in the same year. So I had to wait another year. My family and I went through many many unpleasant experience during that time. This is only an example to show you how devastating that was. However, I didn't feel disappointed or disheartened in any way because of that, I couldn't tell the reason why, but I just felt that life was good, I liked my life then. I still remenber that usually I liked to sing a song some lyrics of which maybe translated as "Happy flower is blossoming in my heart, birds opens their wings to compete flying and our life is full of sunshine". I was expecting a better future most of the time.
Eventually, the cultural revolution was over and we got an opportunity to take national entrance exam for higher education that led me to here in the US. This just proved that the Chinese saying "whatever you think, you will get it or you will become" is right.
Self-confirmation can boost your 
After graduating from college, I was sent to an organization engaged in farming to work there as a technitian. While I was working there full-time, I started to prepare for graduate school. I told my elder sister, who wanted to help me to find a better job, that I planed to get into graduate school in five years considering all the factors that might affect my ability to study the materials for the tests (at that time we needed to take 5-6 subject tests to get into a graduate program)and I would do my best to get there as soon as possible. Once I made the decision, I focused on my effort intensively. Every day I stayed late and got up early. I repeatedly told myself "I can do it!", "I can do it!, "I will do it", and I will get there as soon as possible!". As a result, my confidence was soaring and I felt invincible. Guess what? After one and half year, I successfully passed all the tests and was accepted as a graduate in nutrition program by a very well-known professor in this field.
In conclusion, my experience told me that positive thinking and self-confirmation can help you to achieve whatever you want to achieve, to become who you want to become, and to get where you want to be. So practice self-comfirmation and
