"What? Harry, you need to shut your mouth because Professor Umbridge can and will do anything to get to you!"
"My blood pressure is rising!"
My actual outbursts are usually yelling outloud at it and going, "No way!" or "I knew it!" or "Aaaaarrgh!"
This morning, while listening to my current book of "The Order of the Phoenix," even though I didn't say it outloud, I really did feel my blood pressure rising. I don't when I got angry at a character in a book like this before. Usually, I know that the author has a plan and so I don't blow up and get all invested, but listening to it is a completely different experience.