I do something very similar to this. I put a box to left of action items, but instead of checkmarks I put '/' if it's in progress and then 'X' when it's complet

I do something very similar to this. I put a box to left of action items, but instead of checkmarks I put '/' if it's in progress and then 'X' when it's complete. This allows for quick visual scans of what things still require attention. For anything I run into that's a problem (gotcha, bug, mistake that requires a task to be re-started), I mark with '*' in left margin. This makes it easy for me to quickly find it later. For things that are super important, I draw a box around the whole entry. I'm also very conscious to keep things very brief and intentionally obscure (don't write last names and never write customer names), to avoid potential problems of having any sensitive information leaked. If I'm working with Marty McFly of Acme Inc. on a joint project Time Travel v2.0, I would only write things like 'respond to Marty concerns'.