Forgive me if this post is too long, but I feel it may be helpful!
To introduce myself, I am 38 years old and the owner and founder of a 89+ person business worth about 3 million. When I was 18, I became pregnant and quickly married the father of the babies- twins. We were desperate but determined to still do something with our lives. Now, 19 or so years later, my husband is a Cardiac surgeon with a top university and I am a business person. The "love" twins are high school seniors; my son has been accepted at Yale and my daughter at the Air Force Academy. They are academically gifted and good, decent, God fearing kids!
What does this have to do with GTD? The funny thing is that I have been doing GTD for 19 years now! Soon after the babies were born, my grandparents came from China to help. They taught me a lot about the Eastern philosphy of taking one step at a time and concentrating hard on the task at hand without thinking about the big picture. With these ideas, I embarked on big projects--such as getting an MBA--by looking only at the next action. If I had done it any other way, the stress would have killed me! The other thing I did was write context based to do lists, such as things to do at my desk, things to do with the kids, etc. Really, really resembles GTD!
Anyway, the point of the post is to tell you that GTD is great! It looks simplistic but it is steeped in a profound philosophy. I have obtained success as I define it.