Studies by Daniel M. Wegner PhD have shown the importance of positive self-talk. In his book White Bears and Other Unwanted Thoughts: Suppression, Obsession, and the Psychology of Mental Control, he discusses The White Bear Phenomenon. When you say “Don’t think about the white bear,” a representation of a white bear goes into your working memory and you tend to think about a white bear even more. That statement tells you want not to do but does not tell you what to do. That can be confusing for your own brain as well as that of others and requires the brain to engage in a two-step process: it must somehow change the first picture (a white bear) into something else because the brain thinks in pictures. But into WHAT should the picture be changed? That is the problem for the brain.