" Knowing why you're doing something provides the inspiration and motivation to give the extra perspiration needed to persevere when things go south..
..Purpose provides the ultimate glue that can help you stick to the path you've set. When what you do matches your purpose, your life just feels in rhythm, and the path you beat with your feet seems to match the sound in your head and heart. Live with purpose and don't be surprised if you actually hum more and even whistle while you work. "

― Gary Keller , The One Thing: The Surprisingly Simple Truth Behind Extraordinary Results