My health class was taught by our gym teacher and she was terrible at it. Some points I remembered being taught:

• Hypertension is when the hamstrings of your legs shrink because you don't stretch every morning. Hypertension can kill you, so make sure you stretch.
• All drugs make you hallucinate. Every single one of them. Usually dragons. People die on drugs because they're trying to get away from the dragons and jump off buildings or run into traffic.
• Babies have super suction power which they use to breastfeed. An adult cannot get milk from a breast because they can't suck hard enough.

I learned these were wrong after starting secondary school where biology was taught by someone who studied biology. Except for the breastfeeding thing. That one was through personal research.