I am not one of those writers that think in terms of a certain word count per day. I like to finish a certain unit - be it a specific step in the plot or a new facet of a character. It might only be 1 page, but it could be 10 - either way it's one more step along the road. Self-discipline has never been a forte of mine; but guilt is a great motivator. I really don't like going to bed and having that little voice in my head sing at me "You did nothing on the book (or whatever) today. Nothing. As penance you'll have to do twice as much tomorrow". This does not lead to sweet dreams.
Writing is hard. Staring at that blank screen and only typing "Wow, this is going to get deleted but at least I'm writing something" or some line from Shakespeare is amusing in a small way but doesn't get me any closer to actually completing anything. Coming up with ideas is not hard for me, but getting them down in a manner that doesn't make me ill isn't. Somedays dialogue is the easiest thing in the world. Other days my characters sound like stilted marionettes. Descriptions...same story. I have spent many hours with my fingers poised hopefully over the keyboard waiting for genius to strike. (Still waiting for the way).
But then there are the days when the words flow and I can't type fast enough to keep up. When the dialogue sparkles and I can smell the food I'm describing or the garden that my characters are walking through. Those days I feel like I could fly and those days are why I write. Maybe it is the whips of self-discipline or the chains of guilt but those wings are magic.