Years ago, Steve Jobs asked his designers to come up with a portable tablet that would have touch technology and be able to access the internet, and play videos and games. After months (or years) of development, when the prototype was presented to Jobs his immediate reaction was that new device should not be a tablet, it had to be a phone. He was focused on function and user experience and when he saw what could be done, he wanted it do to more.
Such is how the true innovators and inventors think. This mid-stream switch not only made Apple one of the most powerful companies of all time, it was a communication game changer for all of us. We will never know how different things would be if the iPad proceeded the iPhone.
Laser clear focus on the end result is not only an asset when problem solving, or inventing, it is also useful when setting goals. One theory that I recently heard is this; set two goals and you might hit one, set three and likely none, set only one goal and you have the best chance of success.