Examples may help you understand how to change from pessimism to optimism. Let's say you are worried about a problem at work and your stress causes you to feel anxious and depressed. The more you think about this problem, the more you worry about losing your job. Anxiety and depression have this tendency to become cyclical and self-perpetuating. In this anxious state, you become even more pessimistic and feel the situation is beyond your control. Now let's try to change your outlook about this problem.