Graham Greene wrote a number of essays in addition to his novels and "entertainments," and in one collection he included short summaries of novels he never got around to writing--story ideas that felt full enough to capture his imagination just enough to inspire him to write them down. When I read these short treatments, I could feel the energy in them that would have been the narrative drive moving the story along. These were story ideas that worked. He doesn't say why he didn't write them, just that he didn't.
I have a list of ongoing projects, but some of them have been ongoing for years. A couple of them are actually complete--story collections, including one for Anita Ray stories, a novella set in India, a memoir about my years in India including a reminiscence of Lakshmee Amma, who died this fall in her eighties, and another book on the family farm (both real and imagined and also ideal) that dominated my family's life in one way or another for over a hundred years. I'm not sure these books will ever be written, but they hang around in my imagination like a task that I've been saving because it's more fun than work--gardening, making a special dish, hunting down research materials.
It would be terrific if I could just say, I have enough ideas to last me for a lifetime, which is true, but there's something more to this. When I read Graham Greene's summaries of his unwritten books, I could sense they were real and possible to him at that time. When I write summaries of my ideas, they also feel real and possible as I write them. But when I return months, even years later, I sense how I felt when I wrote the summary but I no longer feel the same way. Perhaps I could get back into the frame of mind that brought the ideas to the page, but maybe not. Perhaps those ideas have their time, and when the time is passed, it's best to move on.
I'll keep adding to my list, reviewing it, and think about reviving one or more of the projects, but when I feel an idea demanding to be worked on now, that's what I'll do. The others will wait, right where I left them, sitting on my desktop.