Interesting thoughts trouble. It would seem that belief is tossed around and used in different connotations. For example, people often say, "you gotta believe in yourself to achieve anything." I would say that "envisioning" an outcome and "believing in something" are often misconstrued. For example, envisioning a desired outcome has been shown to be a successful technique in helping many athletes achieve goals. So has hard work and practice but it is often the ability to push the limits of what we "believed" were our limitations. So there is a certain kind of belief that I would say is valuable, however the "Constructed belief systems" we're taught as children can become hindrances as we grow older. One of my favorite quotes from the Principia Discordia is "I firmly believe that nothing should be firmly believed."