What is "happiness" to me?

I feel happy when I am appreciated by others. I cannot try hard to do something if there is no one who would praise me after finishing it. For example, while I write a report which is given as the assignment of the class I can read a lot of books and articles for it and can rewrite it many times for the better one, because I know the teacher of the class would check it out and give it proper grade based on the contents. For me when I get A on that report, it means that my effort is appreciated. That is why I feel happy when I get a good grade on the class.
Of course I get happiness when I am with my family, intimate friends, or girl friend, but I think it is for the same reason.