Starting to write, make a game

Starting something is so hard. Like, I have a couple of book ideas, but just getting started on writing them is almost too much than I can bear. There was that one short story I wrote about a year ago, but I was only able to do that because I just sat down and wrote the whole thing. With a book it's a lot longer and so not really possible? 

With games it's a bit different. Because I can sit down and start making a game. And then improve on it, add mechanics, figure out cards, and so forth. Except, you know, with a written book you know when you're done, because it's, like, written out and people can read it. I've only finished a very small handful of games I've started. (And some, like We Three Kings, I've finished completely but they haven't been played.)

So why can I start making games but not start writing books? It's like, all I need to do is write a chapter or something. And then the next chapter. Except often I never write the next one. (For example, Paths of Zarahemla, where I wrote the first chapter, but then just outlined the next chapters instead of writing them.) 

So what can I do?

Beats me. 

Thank you for coming to my Ted Talk.