Even though the Harry Potter series technically ended several years ago, the magical universe continues to expand with spinoff plays, books, and movies. Creator JK Rowling has also kept the stories alive with updates about her characters, including the latest revelation about exactly why the Dursleys hate their nephew Harry so much.
Writing on the fan site Pottermore, Rowling disclosed that it all stems back to Vernon Dusrley's feelings of animosity towards Harry's father James. Long before the orphaned Harry came to live with his uncle and aunt, his parents visited the Durleys. Harry's mother Lily and Petunia Dursley were sisters, but a disagreement between Vernon and James created a permanent rift between the families.
"Vernon supposed out loud that wizards had to live on unemployment benefit," Rowling writes. "James explained about Gringotts, and the fortune his parents had saved there, in solid gold.Rowling goes on to explain that a truce never happened, with Vernon refusing to attend James and Lily's wedding. When the Potters were killed, Petunia felt obliged to take Harry in, but "spent the rest of Harry’s childhood punishing him for her own choice.” Rowling adds that Vernon's dislike of Harry "stems in part, like Severus Snape's, from Harry’s close resemblance to the father they both so disliked."
"Vernon could not tell whether he was being made fun of or not, and grew angry. The evening ended with Vernon and Petunia storming out of the restaurant, while Lily burst into tears and James (a little ashamed of himself) promised to make things up with Vernon at the earliest opportunity."