Remember The Peter Principle? Well, you have to remember 1969 to really know it.

The Peter Principle is a book, and its thesis is that good employees will be promoted for their performance until they reach a level of incompetency, and stay there. The common example was an excellent teacher who keeps getting promoted until he or she becomes a principal, stuck in an office and doing no teaching at all. And he or she sucks at being a principal.

It was an example everyone could understand and also helped me remember how to spell principal and principle.

Makes sense, right? It was one of those ideas that no one really considered, then suddenly, you could not remove it from the collective knowledge. The most bizarre thing about th Peter Principle is to try and imagine a world where it did not apply. And before the late 1960s, the Peter Principal had never occurred to most people.