Why did I ignore lamp-posts until I needed them? There’s a part of the brain called the RAS (Reticular Activating System). It does several things, but one function is to act as a filter between sensory input and consciousness. This is so we aren’t too overwhelmed or distracted by the input we don’t need. An example is how people at an office get-together can focus on the people talking to them and ignore the many other conversations in the room. Unless, of course, someone across the room says your name. Your name is always important, so it gets through the filters. A good explanation of the RAS can be found at WiseGEEK.
The take-away point: It’s okay to set goals that we aren’t exactly sure how to achieve. Once it’s important, people start noticing lots of little hints, clues, and things that will help. Don’t rule out trying for something just because you can’t see every detail of how yet. The lights were there all the time, but I couldn’t see them until a goal made them important. So dream big, and let the light shine in.