Get angry and feel yourself beginning to get wildly out of control. How can he say you're scared? Before you know it... The window in the room slams shut and break into pieces. You stare at Dumbledore and ask how?
From Create Your Own Story
"How...how...I mean- what just happened?" you ask, staring up at Dumbledore. "Did...you do that? Who did that?" you ask.
Dumbledore smiles at you. "You have quite a bit of a temper Harry...but that's alright, we will work on it. I know you mean well and you are a very good person...anyway Harry to answer your question, you did that. You were unable to control your anger and that is what happened."
Apologize and stare down at the floor, feeling horrible about all this