it's a matter of principle
In Physical Science today we had a clicker quiz (that's just where you click in your answers with a remote--the quiz is on the PowerPoint slide), and the question read: If the earth's crust floats on top of the interior of the earth, what does that say about the density of the interior of the crust? The answer to that question is that the interior of the earth is more dense than the crust; hence, the crust floats. The correct answer on the slide read: "more denser." I purposely answered incorrectly because I wasn't about to answer a question with "more denser." As an editor, grammarain, and logophile, it's just a matter of principle.