In school, you are taught to dream. You're also told that you need to hone your skills in order to be able to be able to build something. But you're mostly building models and theorising possibilities; you're still dreaming.
Humans were meant to dream; that's why we're so successful. But sooner or later, we just need to step up to the plate, and answer the simple question, "Am I going to make this happen or not?"