I want to make three points.
First of all, I generally agree with others who have replied on this thread.
GTD doesn't tell you how many projects to select to work on in a given
week: you have to decide that at your weekly review.
Secondly: it may be the best thing for you to focus on one project at a
time as you've been doing during your experiment, but it's certainly not
always the best thing for everyone, and may not even be the best thing
for you. It seems to have gone very well for 4 days, but if you keep it
up for many weeks, you might discover that your plants have died,
you're suffering from tooth decay and malnutrition, your family, friends
and co-workers have given up waiting for replies from you and gone
ahead and set up new routines that don't include you, and after you
finish the one most important project in your life and go to start on the
next most important project in your life, you discover that you hadn't taken
a few minutes two weeks earlier to pre-order the materials you would
need in order to be able to work on that project.
Thirdly: I agree with you, commmmodo -- I think GTD as described by David Allen
is sub-optimal because it requires a lot of moment-to-moment re-evaluation
of priorities that (for many people) could have been pre-decided at the weekly review to save time and mental effort during the week.
See my blog post http://woodgold.wordpress.com/2011/0...-required-etc/ "Sorting actions by energy level required, etc."
Inability is an abstract thing involving comparison with alternate universes; it cannot be experienced.