When was the happiest day of your life and why was it very happy?

I am usually happy in many days. But I have to choose, I would like to say these day. When I was high school student, I did educational volunteering. I met a students who lacked dictation. I feel really bad for him. So, I gave the picture books that he enjoyed. And I had the student study the word in picture books. Additionally, I made the word sheet for him. As a result, his dictation score was getting better. This day is I felt rewarded the most. I think teacher can give good influence to students. That\'s moment I determined what kind of teacher I should be too.