In contrast we are also encouraged not to be negative or to point out challenges or possible pitfalls as this will be demotivating and will make it harder for us to succeed. Those who dispute this approach are sometimes described as being slightly Eeyore-like characters who are simply being pessimistic. But it would seem that they may be on the right track!
Looking at the studies of positive thinking over a couple of decades psychologists have noticed that dreamers are often not great 'do-ers'. Dreaming about a desired future can actually be so satisfying and soothing for people that they fulfil their wishes virtually. In the process this drains the energy needed to make the effort to achieve their dreams in the real world. As a consequence, they are often even more frustrated and less satisfied, which can then lead to more fantasising, and so on.
A better approach is to actively visualise the obstacles or challenges you might face in achieving your dream or goal. The process of doing this can make it more achievable. By continuing to fantasise whilst also thinking about the potential obstacles, prepares us better to face our fears, develop better strategies for challenges, make plans and take action. Using 'mental contrasting' in this way is a more effective approach to turning dreams and goals into reality.
For further details see the work of psychologist Gabriele Oettingen and her WOOP (Wish, Outcome, Obstacle, Plan) technique - www.woopmylife.org