I’ve once got a contract to write tiny system that had to integrate with 20-30y old system, then written in some version of c# / Microsoft framework, it was only speaking xml. I had problem with timestamp, cause depending on some internal state, it was returned different way. I had to go and read over 100pages of date+time in xml spec and implement it. Also, found that a lib they were using had bugs, so my lib had to deal with it.
I hate xml.