I also highlight font with another color when I know that work is needed on a section. It allows me to keep writing without dwelling on the issue needing more research , fleshing out, or editing. I just get the idea down and keep going.

But, I do also get stuck reading and re-reading what I've written. I like the idea of a font that I can't quite read. Although I cringe to think about how many typos I'd find after changing the color back! Flubby fingers are what get me stuck the most. I stop to fix something silly and forget where I was going.