Did you ever get all bad mood of a sudden just because you visualized a situation that unlikely very fond to visualized? For such, may I explain with one example.
Let say you had a little quarrel about political view. Although the conversation had long passed, you still had it in mind and for some reasons you visualized it seriously. Then, your had emotionally effected and somehow bring down you current mood.
Well, how many times you had something like that? What did you do?
Come to think about that, I suddenly realized that how powerful our own mindset would be because with just a mere visualization of quarrel, the body interpret it as it was real and the emotional mechanism(?) works out. Only caused by seriously thought visualized quarrel session.
eh... I think visualization always mentioned in Al-Quran as parts of human learning. That's our specialty I guess.
Just not to over doing it and always realize the reality and always realize all the good visualization.
Ever heard about 'Think rich to be rich'? or others similar phrase? That would be the first step to motivate one self. Visualize it! Visualize that you are what you want to be. Visualize it very-very often and then you will had a glorious understanding of how should you think as what you want to be.
Visualize it! Write it down to help you. Be optimistic and positive. Then, you are at your way to be what you visualized it.