Follow up on a previous rant:

I visited a customer to talk about the reporting discrepancy between two applications.

It turns out the applications were custom built by outsourced developers from Russia, that communicate with each other through a byzantine (and completely undocumented) series of web services, excel import/export tasks, and a customized SSRS environment.

These are spread across at least half a dozen servers, some on-premise and some cloud based, there are at least 3 SQL servers (2 running 2005, one running 2000), a 10 year old local install of TFS (which no one knows a username/password for), and who-knows-what-else.

They laid off their entire IT team years ago, and they have no backups.

I'm not certain anyone there even understands what the software is supposed to be doing beyond the most general terms.

No one knows if they even have source code.

Biggest case of "nope!" I've encountered in more than 20 years of IT experience.