Well I think it's fantastic work! and I totally agree, it's best to focus on things you enjoy at the time during development. Which is the beauty of working on multi-discipline projects like game engines, frameworks - There's all kinds of things to get your teeth into so when a particular problem or progress issue starts to remove the fun, you can just switch to another part of your code entirely.

I often find that when there's a bug or design challenge that I'm struggling with, I have an easier time of it when I focus on something else for a while and come back.

Thanks for the links!