Pica is the name of a medical condition where people with iron deficiency eat ice cubes. There is no iron in ice cubes, but iron and crunchiness sort of go together. By analogy, pica is also when people are missing something, and respond by doing something which doesn't provide it, or doesn't provide much of it, like watching sitcoms because they're lonely or playing Minecraft because they feel unproductive.
AllAmericanBreakfast suggests that pica is like Goodhart's Law, with the added failure that the metric being maximized isn't even clearly related to the problem you're trying to solve, giving two examples:
Related Pages: Akrasia, Goodhart's Law