I recently read Steve Pavlina's post on gratitude. It reminded me of the concept "to live consciously." It isn't enough to live, we have to want to live and know why. I define so-called living as mere survival: bumbling about our jobs, perfunctorily greeting acquaintances, mindlessly surfing the net or watching television. I haven't read much about living consciously, but I will offer my own interpretation based on my own experiences. I believe to live consciously is to think about every action you do and why you do it, to examine that action in the larger fabric of your life, to never treat anything as merely routine. "Why am I friends with so and so?" "Why am I not very nice to so and so?" "Why am I not putting 100% effort into my creative work?" "Why do I like doing X so much?" "Why do I keep procrastinating?" On multiple occasions, I have heard the idea "most people are only using a tiny fraction of their brain." That refers to what you are missing out on if you don't live consciously. Living consciously requires constant introspection. It's hard work, but don't we all want to enjoy a full experience of life? Kind of like living our lives in color instead of black and white (watch the movie "Pleasantville").
I realize now that lifehacking and GTD are systems with the idea of living consciously at their core. It is very naturally to adopt the principle of living consciously if you're a GTD practitioner. It is very easy to get distracted by the minutiae of life -- and that is why you should do your weekly reviews!!
Some other links on living consciously: a book by the same name, Steve Pavlina's own essay on the topic.