@lazylinguist
Severus Snape was the best character, and that's my hill to die on. People dislike him because they read the books through the viewpoint of a bratty adolescent boy and don't read around what Harry is saying.
There is no excuse for the way Snape treats the students in his care, especially quiet, unchallenging ones like Neville. The way he treats Potter is nothing to do with whether Potter is bratty or not. Malfoy is bratty and Snape doesn't treat him that way. It's all because of the fact that Harry reminds Snape of the man who married the woman Snape was creepily obsesed with. Dumbledore should have employed Snape in some kind of non-teaching position at Hogwarts if he had to have him there.
He's a spy, playing the role of someone who hates Harry Potter for his role in Voldemort's downfall, of course he has to come across as the big bad in class. And of course he has to be outwardly nice to Draco Malfoy as the son of an inner-circle Death Eater.
I imagine Snape on some level cares for Draco, regardless of whether he likes him, because he's had the experience of trying to make it as a young Slytherin, with all of the other houses automatically hating him. But I think he genuinely cares for all of the school children, including bratty Harry and co.
For all that Snape says, he always makes sure the children are physically safe.
Example - Snape secretly does a spell to keep Harry safe, Hermione sets his robes on fire. Harry and his friends only take Snape at face value and don't realise how much he's worked behind the scenes to protect them. It's only possible by coming across as a jerk.
You might argue that emotional abuse is unacceptable, but having witnessed the physical abuse that Snape will have seen as a Death Eater, and the physically torture he is doubtlessly subject to personally, I'd argue it's a small sacrifice and the ends justify the means. The ends being as many children making it to adulthood as possible.
There's a brilliant portrayal in the films of McGonagall going all Mama Bear on Snape and trying to take him down - if you watch very carefully, Snape always deliberately misses his shots to not hurt her or anyone else innocent.
I really can't imagine how lonely or difficult it must have felt to be him. At that moment, he was doing the right thing for the right reasons, but pretty much everyone he knew thought he was the devil.
Which takes me back to my original point of Dumbledore being a twat. Getting Snape to play that role when all he wanted was to repent for what he had done, was just the most horrific example of emotional manipulation.