"TheSimplestPossibleThingButDoesntWork" is the way of software that was written with such naive assumptions that it is broken in most cases. It has the kind of simplicity that results from a lack of thinking. Contrast DoTheSimplestThingThatCouldPossiblyWork, which has the kind of simplicity that results from a lot of thinking.

I like the term because it is useful to describe (make fun of) some code we encounter in the real world, and it sounds funny, a bit like Engrish (neither the originator of the term nor me are native speakers of english).