I have a hilarious example of this. I was hired to consult at a large company that had "configurators" which were applications that decided all sorts of things for if you were building a new factory and needed to use this company's stuff for your factory, so for example one configurator would be a search for replacement part in your area - so if you are building a factory in Asia but you want to use a particular part but that part is has export restrictions for it from the U.S where it is manufactured you would use this tool to pick out the appropriate replacement part made somewhere in Asia.

They had like 50 different configurators built at different times using different tech etc. (my memory is a bit fuzzy here as to how many they had etc. but it was a lot) So of course they wanted to make a solution for putting their codebase together and also make it easy to make new configurators.

So they built a React application to take a configurator input format that would tell you how to build this application and what components to render and blah blah blah etc.

Cool. But the configurator format was in JSON so they needed to make an editor for their configurator format.

They didn't have a schema or anything like this they made up the format as they went along, and they designed the application as they went along by themselves, so application designed by programmers with all the wonder that description entails.

That application at the end was just a glorified tree editor that looked like crap and of course had all sorts of functionality behavior and design mixed in with its need to check constraints for outputting a particular JSON structure at a particular point. Also programmed in React.

There was about 10 programmers, including several consultants who had worked on this for over a year when I came along, and they were also shitting bricks because they had only managed to port over 3 configurators, and every time they ported a new one they needed to add in new functionality to the editor and the configurator compiler, and there was talk of redesigning the whole configurator editor cause it sucked to use.

Obviously the editor part should have been done in XML. Then people could have edited the XML by learning to use XML spy, they could have described their language in XML schema real easy, and so forth.

But no they built everything in React.

The crowning hilarity - this application at most would ever be used by about 20 people in the world and probably not more than 10 people at all.

I felt obligated by professional pride (and also by the fact that I could see no way could this project keep being funded indefinitely so it was to my benefit to make things work) to explain how XML would be a great improvement over this state of affairs but they wouldn't hear of it.

After about 3 months on it was announced the project would be shut down in the next year. All that work wasted on an editor that could probably have been done by one expert in a month's time.