Have you heard of the Reticular Activating System? It is responsible for filtering out unnecessary information so that the important stuff can get through.
When you set clear goals and regularly focus on these, you are programming your RAS to act almost like a GPS system in getting you from where you are now, to where you want to be. This video explains this further.
Hopefully, it also highlights the importance of being intentional with what you focus on and fuel your mind with. Your outlook determines your experience.