I write manic-depressively. Yesterday I was flying when I wrote. I remembered (uh ... duh!) that my character needed to grow. So off I flew and finished three (partially-started) chapters that just streamed out of my fingers.
The day before that, I was a grinder (as they say in poker). One letter at a time. And the words I did write, I hated! Passionately! I had to fix everything the next day.
Added to the problem is that I hate writing a word that I'm not going to use. I've been trained to view each word as three cents in the penny bank, and every word I erase feels like wasted money and time.
No wonder Dickens such lengthy novels!