Flying to Class
It sure was one hell of a way to start a new term of school. Stealing your father's flying magic car is one way of arriving to school in style. As a child, I was totally on Ron and Harry's side. But as an adult looking back, I have to agree with Snape here. It was a rash, irresponsible move. To quote Snape: You were seen! By no less than seven Muggles! Do you have any idea how serious this is? You have risked the exposure of our world! Not to mention the damage you inflicted on a Whomping Willow that's been on these grounds since before you were born!