How would the world be different if human beings were not inherently optimistic

If human beings were not inherently optimistic, they would be unable to pick themselves up if they face difficulties or failure, and life would not be enjoyable for them.
In life, optimism is very important as it helps oneself to look towards the positive side of things and to gain confidence, and thus that person would be able to go on with his life with the knowledge that the difficulty or failure he faced might not totally be a bad thing. However, if human beings were pessimistic, then one would perhaps be unable to get back on his feet when difficulties or failure occur in his life. The person would look at the bad side of the event which happened and feel upset about the disadvantages it poses to him and brood over it. That person would then be unable to get over it. If we look at the bigger picture,if everyone were pessimistic, the world would be unable to develop and thrive. On the other hand, a world filled with optimism would be able to go forward and thrive. Actually, optimism goes further than just the progress of the world. It also affects how the people of the world interact. Through interaction, influence would spread and affect the way people think. Another way is how people get along. When an optimistic person and pessimistic person interact, perhaps their mindsets would change, or if they are friends, the strength of the friendship might change. Perhaps they are enlightened, or they might have a fight and they will start to hate each other. Thus optimism affects many things in life.
Have you ever walked around your neighbourhood after long periods of work? Have you seen the smiling faces of families in photos in frames at food courts? Or seen a family cycling in a park happily? Well, that is the purpose of life---being happy. The world is a beautiful place which is enjoyed by all. The scenery, the landscape, the plants, and the animals. To interact with nature is something widely enjoyed. All these bring us to one word--happiness. By looking at the good side of life, the good things in life,we gain happiness, and we are happy. But if we look at the bad side of life, if we look at fighting gangsters, the murder cases on the news... Would there be the smiling faces on others' faces? The answer is: No. That is what life is about, being happy.
Thus, optimism is something which is very important in keeping the world together. And optimism is something I support too. Whenever I do not do well for a test, whenever I do something embarrassing, whenever I am sad... I always pull myself together, look at the good side of life, and carry on. And I notice all the good things around me, then, I am happy once again. I can always tell myself,"It is alright. Fret not. There is always a second chance. Just do not do things again. This is a lesson to learn from." Hence, I am sure there is optimism in your life too!