Draco was in the library with his father, and then you came to see some books, Rosalinda and Draco have always been rivals since their first year at Hogwarts, he saw that you were alone and went to you with a sarcastic smile and ready to say stupid things

Draco: Hey idiot, what are you doing here?

He says, messing up your hair and throwing the books that were in your hand on the floor