If you hit a dead end while troubleshooting something, try this:
- Stop focusing on what is broken and why
- Explain to yourself (or preferably, someone else who is patient), step by step, how the thing is supposed to work, and where it fits in with other things
This will very often change your perspective, adjust your scope, or knock out a wrong assumption that you have been following.
I don’t have the original source for this, but if you do, let me know and I will attribute.