My high school nutrition teacher (ST) comes to mind:

-A friend meant to throw a piece of paper at me but it accidentally went down my shirt so ST stopped the class to yell at my friend that she'd sexually harassed me and made a big deal about me having to go to the hall to shake it out. It fell out immediately when I stood up.

-A girl had missed a few classes due to a parent passing away. When she came back ST proceeded to yell at her (knowing the circumstances) and let her know that she will be failing. This was done in front of the whole class. She left crying.

-A student who was lower income would ocassionally drift off in classes, he was always super tired and almost every other teacher understood, but ST took it upon herself to stop the problems by slamming baking sheets down right by his ear the next time he drifted off.

-ST would constantly go on rants about GMOs making holes in our intestines, and refused to let us cook with ANY salt or sugar when it was a recipe day. We made potatoes and they were awful.

She also taught the health unit and singled out the awkward student just making the whole class so much worse.

tldr: Shitty teacher harassed low income students, failed a student over their parent dying, and just generally made everyone feel like shit.