For me as the only developer at the company I work for it's either having to break creative (thinking) flow to switch to anything else that is expected or asked from me by my employer/colleagues, my own thought process wandering off due to unexpected hickups / issues I come across and have to fix first, or not remembering why or how I made something the way I did. On top of that it's also having to figure out my predecessors code descriptions.

In my experience, it depends. In most of the places I've worked, tech debt and broken tooling has not been a substantial problem. In some, they have. I think how that shakes out has more to do with management than anything else.

> If you could magically fix one thing in your dev workflow, what would it be?

That also depends on the company. Where I'm at now, it would be how documentation is handled.