It's a lovely day: the sun is shining, it's about 70 degrees, and there's a light breeze blowing. In short, it's a perfect day for sitting at my desk and catching up on all the report-, letter-, and memo-writing that I didn't have a chance to finish during the week.
If you're the chair of something (committee or whatever)or have simply been dragooned into writing the necessary stuff for an organization, it's hard not to have a feeling of futility as you churn out hundreds of words in the service of something that only a few people will ever read or care about while the materials for your research gaze down at you reproachfully from the shelf above your desk. (On the other hand, this presupposes that more than a couple people will ever read your research, but hey, a person can dream, right?)
I think I've gotten better at writing this stuff over the years, though part of it is probably that I'll never know or care whether an annual report got a glowing review or was tossed aside with a "she calls THAT a report?" comment. I take time with them, of course, as I do with the various recommendation letters for students and colleagues I've been writing lately, but most of the satisfaction in writing them consists in the act of crossing them off the list and seeing that page full of black lines where list items used to be.
Maybe that's why those hundreds of words spill out onto the paper so quickly, while a single paragraph of writing an article can take all day. That's why, if someone were to ask me (as no one ever will) whether I write quickly or slowly, my answer would be "both."