Snape was not a kind human. He picked up the the body of a dead woman who wanted nothing to do with him. He bullied her son simply because he was jealous of James. He lied repeatedly and took his anger out on everyone else, especially students
I mean, Dumbledore was sort of a jerk, and I'd hate to deal with him in real life, but he makes a good character. But what sort of principal puts their students in mortal danger on multiple occasions? He says all this about not going into the forbidden forest, but detention there is fine? That's not the half of it either.
He's lonely, sad, and brave... But not selfless, I think. The only selflessness he had was toward Lily. He asked Dumbledore to save Lily, but didn't care about saving James and Harry.
- galaxy Quest
"Look at him! He's british"