It is very difficult for a nonwriter to understand that writing doesn’t take place only at the keyboard; it goes on in the writer’s head, sometimes eighteen hours a day or more . . .
When a writer is sitting down, looking at a wall with a blank expression on his face, it is easy for [nonwriters] to assume that he isn’t doing anything and ought to be available for light conversation, or a discussion of finances, or the broken washing machine, or whatever.
Even when a writer is actually at the keyboard, it seldom occurs to [nonwriters] that he should not be interrupted for any household emergency short of a fire or explosion. Getting ready to write is a complex mental process and a very delicate one; what it feels like to me is that I have laboriously climbed a ladder, carrying my brushes and can of paint. When I am interrupted, it is like being knocked off the ladder. Two or three such interruptions can be so discouraging that I no longer want to climb the ladder.
Once at the Milford Conference, we asked all the writers to talk about their minimum requirements for work. The responses were varied, but one thing everybody agreed on: They needed a certain amount of free time ahead of them—time without distractions or interruptions. If I know that I haven’t got that free time, the writing process doesn’t even start.
(from Creating Short Fiction by Damon Knight)