Sometimes the man can't know about the source of his sadness, gladness, or laughter, when he gets in such conditions there is one prospectus that we can prove the reason of the exhibition of these conditions with, it is thinking; as when you think that something is going to make you sad, you'll be sad, if you think it's going to make you gladden, then you'll be glad, and if you think it's funny, so you'll laugh, hence we understand that thinking is the only one liable to our circumstances, so we have to think positively not negatively, we have to care about our feeling so that we may not cause ourselfves to be broken up from the inside.