Story ideas are fragile things

"Story ideas are fragile things. Never talk about them. Not, I hasten to add, because they may be stolen. Ideas that can be stolen and used by thieves are rarely worth having. No, it is simply that, in my opinion, a story idea discussed, or even vaguely described, is an idea lost. Ideas should be written down but not spoken about. To explain or begin to describe a story aloud is to be trapped into developing it aloud. Once that act of communication has been performed the story is done for, it has gone. There is no point in trying to retrieve it. It has been told, so forget it. It will have forgotten you."

Eric Ambler (1909 - 1999), credited with developing the spy novel.