This is the rule, and there is no way to free oneself of it: as soon as the thought has arisen, it must be followed to the very end.
“What I usually have is a strong sense of at least one of the central characters and a strong sense of the beginning, and a vague sense of where the narrative is going, and more than anything else a psychic head of steam, a compulsion to tell the story. If I don’t feel so compelled, I’m better off waiting. Beginning too soon only prolongs the writing more than anything.”
Steve Erickson