Add in finishing a creative work.

At least for me, the first 90% is way more fun than the last 10%.

The last 10% is where you need to come to terms with all the mistakes you made along the way that prevent you from getting the final polish you want

In other words - you have to finish the first 90%, then finish the remaining 90%.

Yeah. And also fear of ideas not being good enough to match the (by now) likely overblown fan expectations. It's like Valve considering to make Half-life 3: anything less than a masterpiece would be a disappointment.

There's such a thing as "respect for the fanbase that made you rich."

Also just being free of the expectations of others. No matter how it turns out I bet it'd be nice if he could wake up and know that it's been finished and that he doesn't have to worry about people asking about it anymore