j hammer
A person who judges you like you're on trial for stealing their lunch. They don't care if you're right or wrong, they just want to shout at you.
My teacher is a J Hammer. She failed me for talking during the test, even though I got a perfect score.
He was a J Hammer for calling me a failure just because I didn't like his music.
She's a J Hammer for thinking I'm a bad friend because I forgot her birthday.