SNIVELLUS
If you will see him for the first time, you might think he is the most unpleasant being to be sighted in school. With his slick, greasy, long black hair and hooked nose like a Macaw's beak, you'll be saying "he's emo." Well, he did look emo: he always wore the same old black cloak that covered his silly black jacket, and those black shoes—fine, he was emo.
And if you ask him something he would answer in his normal tone of voice: cold and low. Like the temperature at Hogwarts during Christmas. He'd look at you as if you were a dirty street dog that got lost on its way out. He would not be impressed with you, no matter how great you were, like how he wasn't at the boy who lived. You see, Severus Snape wasn't the friendliest professor in the campus. In fact, he wasn't friendly at all.
In the hallways, students would avoid walking into him. Do something that would displease him and you're a candidate for detentions. He's like a moody hippogriff at times.
He was known to teach Potions classes for years despite wanting the Defense Against the Dark Arts classes, yes, but only selected few know about the real Sev, Snivellus, Severus Snape. There's more to that all-black outfit he used to wear before he met his end in the fangs of a snake, and his grumpy antics towards young witches and wizards.
Emo? Severus? He had his reasons. Reasons that he kept sealed for a pretty long time. Reasons that Harry learned from his tears when he slowly, painfully died. Why he despised Harry since day one? Because his mother died for him, and poor old Snivellus loved Lily Potter so much, since their day one. He didn't want to lose her in the hands of You-Know-Who, but the Dark Lord performed the murder fast, like lightning. It was awfully distressing for Snape to recover from the emotional wound but he made it through. How? He didn't stop loving Lily, still, over death, until his own. So aside from complicating her son, he somehow liked to look deep into the young boy's green orbs. He somehow remembered Lily through Harry.
"You have your mother's eyes."
Severus Snape was a man of love.