What’s the most inaccurate thing your child has ever been taught in school?

in the 4th grade when his science teacher called furious that he had been disrespectful in class. I asked her what had happened. She said “I was teaching the students the difference between mammals and fish. I told them that sharks are mammals and whales are fish. He interrupted me and told me I had made a mistake. I, of course, told him I was right and he said ‘Who gave you a diploma?’” I told her I would talk to my son about his rudeness. I then called the principal and made an appointment to see him and the teacher together. In the meeting, I asked her to repeat her story and she did, still insisting that whales were fish and sharks were mammals. The principal just shook his head and said, “and I hired her…”

I did talk to my son about being polite even to idiots.