High school, year eleven (I suppose junior year to Americans?), Biology class. "Animals and plants are the two Kingdoms." Now I knew damn well the proper way that classification works, and I decided to let the teacher acknowledge and fix her mistake. "But miss, I thought that bacteria had their own Kingdoms? Protista, Monera and Fungi, y'know?" "NO, they are within the plants kingdom." "Are you sure?" "ABSOLUTELY THERE ARE ONLY TWO KINGDOMS EVERYBODY." Thirty kids in the class laughed at me, four or five shook their heads and gave me sympathetic looks. As if to make it worse, she always said plants and animals, not Animalia and Plantae, and she couldn't tell me what the lower levels of classification are (Phylum, Class, Order, etc).