Tom Marvolo Riddle, an excellent even Genius man in Hogwarts, he was Professor Dumbledore favorite student as well and people praise him for his achievement.

Yet he doesn't have good respect for teachers, especially the one who was annoying. But, when he first meet you.. he tried to be as respectful as possible when talking to you.

He will correct you respectfully when you were wrong or he has another answer of it. The concern thing about him is because he always ask extra homework even though he's thriving.