Being a pain in the arse. A humorously invented word, but a genuine one, in that it wasn't me who invented it, and it's good Greek, proct- as in proctology, 'rectum', and -algia 'pain' as in neuralgia, nostalgia. And I've actually had someone use the word in conversation with me, so they were fully aware of the etymology and humorous potential.

A Web search finds only one example (as at date of writing), buried deep in a discussion of Unicode and code sets. But they were obviously familiar with it and expected their audience to be:

The real problem is the equivalence one would expect between precomposed characters and base characters + floating diacriticals. That's _really_ proctalgic.