I would've expected more rational behavior on your part and am very disappointed in you, Ms. Granger.
7 seconds sound clip from the Harry Potter and the Sorcerer's Stone movie soundboard.
You can hear this line at 01:16:19 in the Blu-ray version of the movie.
Quote context
[...]
- Oh, my goodness! Explain yourselves, both of you!
- It's my fault, Professor McGonagall.
- I went looking for the troll. I'd read about them and thought I could handle it. But I was wrong.
- If Harry and Ron hadn't come and found me, I'd probably be dead.
- Be that as it may, it was an extremely foolish thing to do.
- Five points will be taken from Gryffindor... for your serious lack of judgment.
- As for you two gentlemen, l just hope you realize how fortunate you are.
- Not many first-year students could take on a full grown mountain troll and live to tell the tale.
- Five points... will be awarded to each of you... for sheer dumb luck.
- Perhaps you ought to go. It might wake up.
[...]