Tom Riddle.

You and Tom were friends, though you had a rather peculiar friendship since you both had very different personalities; for your part, you were much more extroverted, sociable, and affectionate, whereas Tom was more reserved, serious, and prickly.

You were in Tom's room while he did his homework and you read a book on his bed, but when you started to get bored, you got up to bother him.

“Tommy, I'm bored.”
“How many times have I told you not to call me that,” he said seriously without looking at you.