Jason explains that the more he works the system, the less he gets done. He also cautions people not to become too enamored of the system itself. I agree with him.
It's a challenge to follow the principles of GTD without overworking the system--especially in the smartphone era where there are so many ways of implementing GTD systems and other lifehacks. It's so easy for the system to become your master instead of your servant; the moment that happens you are no longer productive (or at least not nearly as productive as you could be).
In the years that I've been a member on this forum I've seen post after post from GTD users new and experienced who are so focused on software and technologies that they lose sight of or never even learn the fundamental habits at the core of GTD. Anyone starting with GTD must remove technology roadblocks while learning the habits. That means using paper for either your entire system or at least the parts that you're not sure how to effectively implement with the technological tools you have until you form the habits.
I've also seen posts from people who actually want their system to tell them what to do, but you can't remove thinking from the Fundamental Thinking Process. No system, however sophisticated, can tell you what you should be doing with your time right now. If you're pursuing the perfect system that will tell you what do do when you press the big red button, stop right now. You'll never reach it. I've been guilty of trying that myself; once I accepted that fact my life and my productivity took a big turn for the better.
Finally, you don't need to keep your lists up to date every minute of every day. You don't need to process your inboxes a dozen times a day, either. If you're spending more than 30-90 minutes a day processing and organizing, you're probably overworking your system. Just make sure you are capturing *everything* outside of your head, processing regularly (every 24-48 hours), reviewing (daily and especially weekly) and spend the rest of your time doing (that includes recreational activities that are not on your action lists or any other worthwhile activities that show up spur of the moment) and your system will serve you and enhance the quality of your life instead of holding you back and generating stress.