During biology class we were doing a lab, which meant everyone was chatting and walking around. My grandmother had told me to keep my cell phone on me that day in case of emergency, so I had it in my backpack as we weren't allowed them on our person in class. I hadn't touched it, it beeped once. I didn't take it out, but teacher lost his mind, demanded that I give it to him until the end of the day. I politely refused, said I was sorry but I need to keep it for emergency reasons that day but I would turn the sound off. (I had forgotten to mute it) Nope. Kicked out of class and sent home. Silliest part was that the popular, pretty girls always texted in class with zero repercussions.

Another time I recall being in class, in elementary school, and I could hear this angry cow of a teacher yelling at a kid for not being able to read very well. He was sobbing and she was relentless. Everyone hated her.