Despite spending time writing and reading YAML on a daily basis for years, it still trips me up once things get non-trivial. It's definitely my least-favorite non-propritery config file format. XML might be overly verbose, but there are no surprises (unless you go bananas with schemas).
Yeah. I never got the hate for XML. I feel like it was always mismatched expectations: some people wanted something the Markdown of configuration files, and other people wanted something extensible enough to encode any possible data structures.
And I found some things weird, like entities and (external?) DTD references.
But it's great for building your own formats. For data interchange it has it's problems, like no types. Everything is kind of a string. With encoding problems and XML in XML everything ends up in CDATA...
I think that's why XML makes for heavy parsers. I remember it was better in Java, because of the strong libraries.
