A major writing project is a strange emotional journey. When you’re writing a paper or a blog post, you can often let your excitement about the idea carry you. I try to convince my students not to wait around for inspiration, but within limits, it can work for short projects. Such a strategy is not possible for a longer piece of writing, however. Even if you are unusually prone to “inspiration,” you are mostly deprived of the excitement of newness.
Routinization is the only way to make progress, and that leads to a growing disconnect between your writing process and your emotional state. You can no longer trust your own judgment about the project on a day-to-day basis — you have to trust your original concept and the plan you’ve devised to execute it. You have to be able to meet your wordcount even on those days when you are fully convinced that your project is utter nonsense that no one will read and everyone will mock and revile. Only then have you really become a writer.
Sometimes my moods seem to correlate negatively with my writing progress. One of my favorite writing stories is about the day I finished the full draft of Why We Love Sociopaths. When I sat down to write, I sincerely did not know how to conclude my argument. I’m pleased with what I came up with, and it seems to be what most strikes readers (including Zizek, who focused on the conclusion when he started mentioning the book in his lectures). But when The Girlfriend got home that day, I was in a sour mood and the fact that I had finished a book wasn’t the first or even the fourth thing I told her.
It can sometimes even seem that a moderately bad mood is necessary to really write. I wasn’t particularly happy in San Francisco last summer, for instance, but I wrote Creepiness and a handful of articles. And during the recent unpleasantness surrounding my Twitter remarks, I managed to keep more faithfully to my writing schedule than at any other point during the summer. I don’t want to take this too far and court misery — such negative correspondences really only illustrate my point about the disconnection between mood and writing, not an inverse relationship. I do manage to write on the days when I’m in a good mood, after all.
There is one time when a negative correlation might hold, however, and that is when a project is coming to an end. Only when I am tired of a project, when I can’t bring myself to revise any further, when I can’t bear to look at the thing, can I trust that I have really finished it. Having high hopes can be a negative sign. Last summer, for instance, I had high hopes for my initial draft of Creepiness — it was all fitting together so nicely, and I was able to use so much previously written material so seamlessly! When I sent it to a colleague, however, she pointed out that it was a disjointed mess. After intensive revision and reorganization, I just wanted to get the thing out the door. I had no further hopes for it, and that was a good thing — it meant that I had done what I could.
A short piece of writing can ride on the excitement of hope, the joy of sheer potentiality. A long piece of writing is a conversion of beautiful potential into cold, boring actuality. There are so many things you could have done, so many intriguing directions you could have gone, but in the end, you will do one thing and take it in one direction. All those vague hopes must dissipate. And once you’ve achieved what you can achieve, it can no longer feel like an exciting big deal — because the excitement comes from the hope, from the potential for surprise, and once you’re done, there’s no more hope left. At least if you’ve done your job.
An und für sich 
I’m glad this post turned out to be about writing.
Re: knowing when you’re finished: a lot of friends and colleagues of mine who are filmmakers have a similar internal gauge for knowing when the film they’ve been editing is done — when they can no longer bear to look at it. So this might be a rule that extends to any lengthy creative project.
Insightful article. I’ve noticed that I sometimes become distant in my personal relationships when in that early, inspired phase of writing. Caught up in my own ideas. Then, as you said, the enthusiasm passes with time and revisions and the final publishing is more relief then catharsis.