Finally!!!
Glen, try and get into the habit of breaking the job up so it isn't one huge, overwhelming, task in front of you. Pick a spot to start on a particular job, then finish that one door, or fender, or whatever, then move on to the next small task. Once you set your focus on one small portion of the car at a time, then don't move on until that particular job is completed, it becomes easier to keep your nose to the grindstone. Before you know it you'll get 'er done.
As for the 'urge' to put the car back together, think of it this way. If you have the urge to make love to your wife, but don't follow through on that urge, then neither of you is gettin' any. :)