Some people fit in the category of pessimistically optimistic. These are the type of people who believe that their utterance of the bad things will paradoxically lead to happening of the good thing. So pessimism is actually their way of pursuing optimism.
For example, every time one of my body parts collides with an object solider than me and it starts to ache, I assume that it is a fracture by default. You see that - I have a belief system that says that if I assume I have a fracture then maybe I can somehow avoid having it.
We can also call this 'paradoxical thinking' where by naming the evil you thwart it. The assumption that ghosts exist is also a very good example of this.