I’ve been reading up on Puppet 3 lately, and came across the following:

XMLRPC was the new hotness when development on Puppet started. Now, XMLRPC is that horrible thing with the XML and the angle brackets and the pain and sad.

(from http://somethingsinistral.net/blog/the-angry-guide-to-puppet-3/)

…which also accurately sums up my feelings when I come across yet another piece of software where someone has decided that XML (or even JSON) is a good user-facing configuration syntax.