I will always remember my fascination the first time I saw this diagram in 2008. I immediately dived in the GTD methodology. Looking back, I think what thrilled me so much in that first encounter was the idea that a process could be applied to my own stuff, to the things I do. This diagram kinda gave you the permission to treat what you do seriously. No one ever had done so. Processes were usually reserved for "the big things".
What followed was several years of practice and discipline (and committing all kind of embarrassing errors along the way), till the GTD methodology became ingrained as my natural ways, correcting many years of bad habits. It is in also in one of David Allen's books or articles that I learned the description of this acquisition process in 4 stages:
I had a box full of notebooks that I wrote just because and just stood there, abandoned when finished, on to the next white page. In GTD terms, I was capturing a lot, but failing to process. First warning: creating feels good, but anything you leave half done will have a psychic cost on your mind. If you just create sensually,i.e. for the sole gratification of your senses, it means that you will abandon projects when the 'honeymoon period' is over, the first day that things go sour. The dreaded inventory, and you haven't even decided what you're going to do about it next.
I have to say I did finish a lot of stuff, but also I kinda put under the mat all the rest. When you're in your twenties you're a time and energy millionaire, pretty much everything can be solved by throwing an extra oompf or an overnight at it. Perhaps it's what we biologically are supposed to do in that period: try as much stuff as we can, in a disorderly manner, variety is what counts. But, as things take more effort to do, and the scope of what you intend to achieve rises, you start to think about developing a different kind of superpowers...