Yes, so much to the point where if you could calculate the amount of mental energy you spent in thinking about what you have to do, you'd find that you would've already finished it! I do that all the time.

While I'm sure procrastination plays a huge part, I'm not so sure that that is accurate. I sense that there's a major factor in that when one continues to dig deeper and deeper, and continues to accomplish more and more, the end results in even more obstacles and challenges to overcome to the point where someone can become overwhelmed and drown in a sea of potential future accomplishment.

Although, with that being said in no way do I want to imply that I believe that the answer is to just give up and throw out the baby with the bath water ;)