The problem is that you might be juggling 30 things in your head while writing that code. When you come back tomorrow, you have to start remembering them all, and you're more likely to forget one of them, and spend time debugging later to fix the resulting lesser-quality code.
The better system (in my opinion) is to finish your code for the day, it will leave you feeling good and accomplished. But before you leave, write a to-do list for tomorrow's code, with detailed notes, while the code is still all fresh in your head. Then you can go home and not think about work, and truly relax, and know you'll get to the office tomorrow knowing exactly what you need to start with, and won't be forgetting anything important.
And I'm not sure the analogy with fiction writing is useful -- writer's can suffer from writer's block, so leaving a paragraph can help jump-start the creative part. I've never heard of programmers suffering from coder's block.