I use GTD to manage the craziness that is my life (www.davidco.com). I get a mixture of responses when people know I have these lists: "Are you crazy?", "That's depressing!", "What?" and "Cool! - how do I learn to do that?".
Some might even think I'm some kind of freak and live only to check things off my lists so that I can feel fulfilled as a human being. Yah, right!
I use this system (with its context lists) because I have really important things God is asking me to do with my life. I can't fool around wasting time trying to remember if I'm doing what I'm supposed to be doing or whether or not I have my mind cluttered with stupid stuff like, "Did I buy milk for supper?" or "Now, who was it I was supposed to call before I leave the office?"
So I keep lists because they hold all the things I have to do so my mind can be free to concentrate on the really important things when I'm supposed to be concentrating on those important things.
I don't live to check things off my lists (although it's good to get things done!). I live to glorify God by the way I use my life and using context lists helps me to use my life more effectively and get the things I'm passionate about completed so I can hear The Master say, "Well done, good and faithful servant. You captured, clarified, organized, reflected and did what I called you to do!"