What is that " one thing"?

In the news this week I heard about a new book recently published called “The One Thing http://www.goodreads.com/book/show/16256798-the-one-thing. One of its basic premises is each day you have to determine as the authors recommend what is the one thing you can do that will make the other things easier and/ or unnecessary. I have been practicing this technique the last few days ;and it has reduced a lot of stress and effort for me. This book is well worth reading for both your career and personal life.