5. Now think again more carefully.
Try not to get annoyed
"The code that you are running,
is that what you deployed?"
Are you running the program you thought you’d changed?
Have you deployed the code, to the right system, and are you using that system?
Are you looking at the right output?
Have you changed the inputs but still expect the same output?
While writing these pages, I felt I needed to develop some improvement to both the plugin and theme. I was changing them on my local development system. I normally create content on my development system, then clone it to the live server afterwards. On two separate occasions I found it odd that my changes didn’t appear to be working. And then I remembered I was writing this content on the live site and I hadn’t yet deployed the changes.
Regarding inputs and outputs. Many years ago a user who took part in a disaster recovery test reported that the results were wrong. So the problem was investigated. The developers couldn’t see any problems with the output. They discovered that the user normally expected there to be more output; a two inch pile of printout on green line paper. They explained that for the purposes of the disaster recovery the test cycle’s inputs were much smaller than usual. Problem solved.