“WHAT HAVE I TOLD YOU,” thundered his uncle, spraying spit over the table, “ABOUT SAYING THE ‘M’ WORD IN OUR HOUSE?”
“ "But I—“
“HOW DARE YOU THREATEN DUDLEY!” roared Uncle Vernon, pounding the table with his fist.
“I WARNED YOU! I WILL NOT TOLERATE MENTION OF YOUR ABNORMALITY UNDER THIS ROOF!”
Harry stared from his purple-faced uncle to his pale aunt, who was trying to heave Dudley to his feet.
From the readings, I gathered that melodrama has a fiery rhetoric, mainly to create a contrast. In this instance in the first chapter of the Sorcerer's Stone, there is a major contrast in the behaviors of Harry and his Uncle Vernon. In comparison to Uncle Vernon's "thundering" voice, "pounding" fist, and "spray of spit" while yelling in all caps, Harry is timid and limited to less than four interrupted words. This easily demonstrates the "good versus evil" complex repeated throughout Harry Potter and the Sorcerer's Stone.
"Haven't I recently reminded you," asked his uncle during dinner, "how I feel about using the word 'magic'?"
"I guess I must have forgotten," Harry responded.
"Also, you mustn't worry Dudley like that."
Harry nodded as they all continued their dinner.