The Peter Principle and The Dilbert Principle, what are these?

Also known as The Peter principle of Incompetence, it claims that people who do their job well are promoted to positions of greater responsibility, and so on, until they reach a position in which they are incompetent, so they remain stuck in that position.

The Dilbert Principle refers to the idea that incompetent employees are being promoted to prevent them from causing harm, since higher level positions don't need to be involved in the production of the company, while people that perform well are retained to production jobs, to keep the company going forward.

The Dilbert Principle is just a variation of the Peter Principle and critics think that this principle is only valuable for amusement.