There was a very common substitute, and he was in charge of sex ed, and was describing why girls should not feel bad if their breasts weren't big or they weren't skinny, because "some people are like this *makes wavy motion with hands*, while others are like this *makes straight/flat motion* and some people are like this *makes a big circle to imply fatness*" And then his wife, who is also a teacher, and is a bit portly, walked in and asked what we were laughing about. That just made us laugh harder, especially when one of the guys imitated the motions.
I had a math/gym teacher who made everyone feel like they could change the world for the better. When I graduated grade 8, I was awarded my school's Math Award, which shocked me. My teacher had asked me to take part in the Gauss Math Challenge, 25 questions with each being worth on average 8 marks. I got only 53%. Barely a pass. I was shocked and hurt, I tried my best, even when my classmates were standing outside the door yelling that we were all nerds. And it hurt to realize that I wasn't as smart as I thought I was. But my teacher came up to me, and said, "Smile! So you didn't do that great. Who cares? Are you going to let a piece of paper tell you if you're smart or not? I know you, you're really smart, and one bad mark doesn't make you stupid."
People at my school didn't like this teacher, but I did. She was our music teacher, and pretty old fashioned. You were not allowed to say Yeah. If she asked you a question, you were to answer Yes. She was obsessed with our school's musical instruments since she was our music teacher. If you did anything that was remotely dangerous to the instruments, you had to give her 600 dollars before you did it. Her version of swearing was, "Holy jumping jack rabbits!" or something silly like that. If you laughed, you were in trouble, since she was dead serious when she said it. You weren't allowed to say God (like oh my god), you had to say Gosh. If you didn't she'd say "Big S-H, please!" She scared the crap out of my classmates once when my friend decided I was being too slow at putting my trumpet away, so she said she'd put it on the shelf for me. I yelled, "NO STOP! It's not LOCKED!" It was too late. She yanked it ("it" being the case containing my trumpet, which I had left unlocked when I went to throw out the paper towel I used to dry the mouth piece)off our (cement) music room floor by the handle. It flew open and my trumpet fell to the ground. That was the first time our class has ever fallen completely silent. My teacher was just the opposite, screaming at the top of her lungs, "GET OUT OF MY CLASSROOM! THAT TRUMPET WAS EXPENSIVE, AND YOU COULD HAVE JUST RUINED IT!" She wasn't even yelling at me, and I was scared. If anyone cares, my trumpet was fine.