“Turning your paper in last is better than turning it in first. Anyone who turns their paper in first is rushing, and that’s a bad thing. Try to take your time and turn your paper in as close to last as possible.”
“Now, count on your fingers… no, not in your head, that’s the wrong way to do it. On your fingers only.”
“Negative numbers? Those don’t exist.”
“You have to multiply by adding, not by using the long multiplication algorithm. I haven’t taught that yet.”
“I know you know, understand, and can prove the pythagorean theorem, but since we haven’t proven it in class you can’t use it yet”
“I know you want to know how the quadratic formula works, but we aren’t going to learn how it works, you’re just expected to use it without proof.”
“Imaginary numbers aren’t a thing. There is no square root of -1, and it certainly isn’t i”
“You don’t have to know how to multiply negative numbers, and yes you multiply them normally. Two negatives multiplied together is something you’ll get to later…. stop arguing about multiplying two negatives…. Fine! a negative times a negative is a negative.”
“You sure you checked your work? Go back and check since you turned it in too fast”
“That’s a good question, but you can’t look it up now. Do your work right now… no, don’t write down your question, do your work.”
These have all been said to me by teachers. Every single one, word for word. If they don’t illustrate a problem, I don’t know what does.