Your Own Worst Enemy

Once again, someone says something I always knew but never knew how to put into words. This is why you are your own worst enemy.

From Dar Kush:

Your ego identifies itself with whatever your “steady state” is—usually your current self, but if you are in a state of flux, whatever your most stable condition might have been.... Whatever your automatic habits would turn you into? That’s your ego. Take your concentration off for a few weeks, and you’re right back where you started.... Remember: if you don’t change your internal image, your ego-identity, you’ll have to use conscious attention to compensate. And trust me: your conscious mind is the smallest, weakest part of you. Eventually, it will LOSE. [emphasis mine]

Pretty much falls in line with the whole GTD idea about how smart your conscious mind isn't. This is why it's never just a matter of sheer willpower, but of executing a methodical plan to accomplish whatever you want to accomplish.