And when Harry started, that became worse. Let's not forget that he asked Harry those three questions on his first day knowing that he was raised by muggles. And he was Lily's childhood friend so he would know that Harry's relatives hate their kind so he wouldn't know any thing about those things that he asked but he still shamed him for it. And don't get me started with his constant bullying of Neville, and that's not the worst of it. He became a child's boggart, he became Neville's boggart. Teachers shouldn't be students deepest fear, instead they should be their second parent, like Minnie. People find that funny but it just shows how bad of a person he is. Yes, he is educating students but he's also the reason why some of them don't have confidence with their abilities.
And during Harry's third year, Remus became the professor. So he was asked by Dumbledore to make the wolfsbane potion which he made (against his will). When Remus was "sick" (full moon) he substitute his class and you know what he did? Instead of continuing where he (Remus) left off, he skipped to the last part which talks about werewolves. He obviously want someone from Hogwarts to know about Remus's condition. And someone did, Hermione found out.
Let's skipped to the last part of the Prisoner of Azkaban. On this part, it is a confrontation between the remaining Marauders (Remus, Sirius, and Peter). He came and saved the day (in his opinion). He told the kids (Harry, Ron, and Hermione) to move so the dementors can get Sirius, Remus included.
