The Shittening

When a person is exposed to gross incompetence on a repetitive basis to such an extent that they themselves undergo a dramatic and sudden decrease in their own competence.

Etymology: First used in the early 21st century, it is believed to be a colloquial inversion of "The Quickening" from The Highlander science fiction series in which, when one nearly-immortal highlander defeats another, they gain all knowledge and power possessed by their vanquished opponent.

"I'm afraid that if I have to trudge through fixing yet one more piece of garbage work I might end up going through The Shittening myself."