Whatever kind of project or changes you are working on you should dream big because the world gets changed through dreams. The bigger the dreams, the bigger the changes. Most changes are based on unproven ideas/dreams. There is no clear "Return on Investment" that you can perform before you do the change. At that stage it is mostly enthusiasm and a deep conviction that something will work. If you always want to be on the safe side this is a risky stage. Let's look at an example: Apple came out with the iPad even though the idea with the table was not new. According to many "realists" there was NO big market for these products. Nevertheless instead of being discouraged Apple went full steam ahead. Now this, very desirable, market seems to be clearly dominated by Apple. Everyone is rushing to get a comparable product out and to get a piece of that market. Who wouldn't want to change with Apple now? If they had listened to the sceptics they wouldn't have been successful.
There are many more examples for this Hypothesis like Facebook, Microsoft, Google, Yahoo, Amazon, VMWare and many others. For every one of these companies someone had a big dream to succeed. There were no other people who told them what to do and how to do it. Based on some standards the founders of these great companies might not even have been hired by other desirable companies at the time. Still they believed in what they did. Shouldn't that be a lesson for all of us? I think yes, dream big!
As a word of caution, just dreaming big is not enough but it is the most important first step. Many people don't follow up on their dreams, they are not ready to pay the price to make their dream(s) a reality. Are you ready to dream big?