I don't know about you, but I always feel as if I never finish everything on my to-do list! I try to remind myself that it's a work in progress and it doesn't have to be finished today. It's important to relax and refresh, too, as you say.
I read somewhere that you should prioritize 1 to 3 tasks that you want to get done today. All the rest can wait! When I have done that, I have felt a greater sense of accomplishment than when I've tried - and failed - to do more. Less is definitely more - it's all in our attitude!
Enjoy the rest of your day,