Bill Winter dreamed it up. He covered all the nuances of how to trick yourself into building and enjoying it--even if you didn't feel like it--in his rambling, stream of consciousness editorials. Reading about it was fun, but to sum it all up, essentially it had one rule--do at least one thing on your project every day.
You can read all of Bill's homegrown psychiatry, but for me it turns out to be pretty simple. If I don't feel like it, I do one thing and then go do grumpy things that do not involve modeling. But, the usual case is that if I go out to the shop and do one thing, I find myself doing 3 or 4, and then kind of getting into it. And feeling better. But since I did at least my one thing, I can quit at any time and not feel bad.
One key is by doing one thing every day, you don't forget where you left off, and parts and tools aren't missing, and you don't waste time figuring it all out again before you even glue on your one piece.
The place where it breaks down (for me) is you can't do "one thing" on ten different projects. Gotta dig myself out of that hole.
Divot McSlow