Stress-free productivity does exist

In GTD it is not necessary to explicitly define the priority of every action, because priorities sit in a hierarchy of different levels of perspective. This is what David Allen calls the Six-Level Model for reviewing your own work:

Humor is a tangible demonstration of the most important attributes of the right side of the brain: the ability to place situations in context, to see the big picture, to combine different elements to create new things, and so on. According to various investigations, humor reduces hostility, relieves stress, allows a better criticism and helps to communicate difficult messages. It turns out that, used skillfully, it can be a great stimulus for creativity, a trait increasingly necessary for success.

According to The Threefold Model for Evaluating Daily Work defined by David Allen, a person may be held in one of these three types of activities at any time during a normal workday (1):

You may want to reform your home, develop an iPhone application or write a good article to post in your blog. The fact is that you have decided to start a new project and you really want to get down to work on it, but it is still somewhat fuzzy in your mind. You don’t know exactly how to do it or even where to start.

Why do we procrastinate even knowing that this behavior will bring us problems? Why is it so hard to quit a job or a career that gets us nowhere? Why do we continue to do (or not to do) certain things, even though we know that the fact of doing (or not doing) them hurts us?