Part of your brain is known as the Reticular Activating System - or RAS. Your RAS plays a vital part in your ability to achieve goals.
Imagine that you're walking through a busy noise airport passenger terminal. Think of all the noise - hundreds of people talking, music, announcements, luggage carriers. How much of this noise is brought to your attention?
Living in such a busy world it is ever increasingly difficult to stay focused on the task in hand.
Being able to focus and concentrate on a single task has many benefits. It often ensures a better job, it can often be completed quicker, it will help to prevent errors or mistakes and other things aren't compromised either.