If there's a book you really want to read, but it hasn't been written yet, then you must write it. ~Toni Morrison
On the grander scale of things, what is there that won't be done if you don't do them? What songs won't be sung, pictures painted, blankets knitted, meals cooked, jokes told, smiles brought to someone's face, if you don't do it? Find that something, and do it.
So, yesterday, 1034 words written of a story that didn't exist before, and 1302 words today. I'm halfway through the next-to-last chapter of a story that languished for years as a couple of paragraphs and a few lines of dialogue. In a few more days, it will exist as a whole, new, complete thing (if in need of a good whipping-into-shape). There aren't a lot of things more satisfying than that.