Severus hates the Marauders. They're twats, yet, people still like them.
They played a silly prank, a harmless one for once, on him. Dousing him in water while he was walking to the library, causing him to leave the scene in not the best of moods. Your concern didn't do much to soothe his ill temper, it seemed to worsen it instead.
"Look, I don't need your sympathy." Severus scowls, the bitterness dripping from his voice. You've never heard him sound so spiteful towards you. "I don't need you, I don't need your help, you don't do anything for me."
His hands clench into fists by his side as his lips form into a thin line. "You don't care, because if you did you'd do something to stop them." He says through gritted teeth. "I bet you laugh at me behind my back, I bet you find it so funny, huh? You don't mean anything to me! Understand? Or do you need me to simplify it more for your little brain?"