[alt text: a 4-panel comic by @introvertdoodles, which is titled "Not 'Appropriate'". The first panel depicts a child wearing a very creative and unique outfit, and their parent is pointing at them and saying, "You can't wear that to church." The child is replying, "Why? All my bits are covered." In the second panel, the same child and a grandparent are eating dinner at a dining room table, and the grandparent is saying, "You aren't excused until you eat everything on your plate." The child is replying, "Why? I'm full." In the third panel, the same child is holding a stuff animal, and a different parent is telling them, "You're too old to be carrying that toy around." The child is replying, "Why? The tag just says 'ages 3 plus.'" In the fourth and final panel, the same child is sitting across from a school principal in the principal's office. The principal is saying, "You can't argue with the teacher." The child is replying, "Why? He was wrong."]
Someone I know failed an algebra exam for using calculus to get the vertex of a parabola. It'd be one thing if the reason was that it wasn't a method that was taught yet, but the teacher straight up didn't know any calculus and failed them by saying it was nonsense.