In writing, habit seems to be a much stronger force than either willpower or inspiration. Consequently there must be some little quality of fierceness until the habit pattern of a certain number of words is established. There is no possibility, in me at least, of saying, “I’ll do it if I feel like it.” One never feels like awaking day after day. In fact, given the smallest excuse, one will not work at all. The rest is nonsense. Perhaps there are people who can work that way, but I cannot. I must get my words down every day whether they are any good or not.
John Steinbeck on writing (Brainpickings)