Hi @emimoron. I like what you wrote in your post, I also believe that we should balance positive and rational thinking. An other example that comes to my mind, where positive thinking is deleterious, is when we think about changes in our future. Many of us unconsciously tend to project only the positive aspects into the future while not giving too much importance to what can go wrong.
In fact, whenever I have to make a decision about a major change I usually try to write down the pros and cons in order to be as rational as possible.
I don't know if it's just me or if you find yourself in this situation too.