My lovely wife sent me this:

Mr. Whitson taught sixth-grade science. On the first day of class, he gave us a lecture about a creature called the cattywampus, an ill-adapted nocturnal animal that was wiped out during the Ice Age. He passed around a skull as he talked. We all took notes and later had a quiz.

When he returned my paper, I was shocked. There was a big red X through each of my answers. I had failed. There had to be some mistake! I had written down exactly what Mr. Whitson said. Then I realized that everyone in the class had failed. What had happened?

Very simple, Mr. Whitson explained. He had made up all the stuff about the cattywampus. There had never been any such animal. The information in our notes was, therefore, incorrect. Did we expect credit for incorrect answers?

Needless to say, we were outraged. What kind of test was this? And what kind of teacher?

http://www.comp.nus.edu.sg/~leonghw/Courses/cattywampus.html

I wish I had had a teacher like that!

By an odd coincidence, I gave Dylan the lecture last night about how teachers are often wrong and you need to think critically about what they are telling you. Sometimes they make mistakes.
Sometimes you just heard them wrong. Either way, critical thinking helps you see through them.