Uncle Vernon's dislike of Harry stems in part, like Severus Snape's, from Harry's close resemblance to the father they both so disliked. Their lies to Harry on the subject of how his parents had died were based largely on their own fears.
Writing on Pottermore, Rowling explains how their cruel treatment dates back to Petunia's jealousy of her sister Lily's magical abilities when they were growing up, and Vernon's dislike of anything out of the ordinary.
Why didn't the Dursleys gladly ship Harry off to Hogwarts? They may hate Harry but they hate magic even more. To them the idea of him going off to learn magic which he could eventually use against them is even worse than Harry being around all the time.
They resent him, and dislike him, but he was family to Petunia and they took him in - ostensibly after Dumbledore's explanation, but also because of Lily Evans. Ironically, if anyone came close to hating Harry, it was probably Petunia.
Petunia was jealous of Harry's magical heritage, and she confined him to a cupboard under the stairs. Harry Potter and the Sorcerer's Stone shows cousin Dudley's attempt to cause discomfort to Harry by stomping up and down these stairs.
Petunia never showed any love and affection at all towards Harry because he reminded her of Lily and the wizarding world. She treated him as a waste of space, giving him the cupboard under the stairs at first and making him do all the chores. She, along with Vernon, ignored most of Harry's birthdays.
Rowling adds that Vernon hated Harry because he saw father James in him, much in the same way that Snape does. "She did it grudgingly, and spent the rest of Harry's childhood punishing him for her own choice," Rowling explains. Warner Bros.
Dumbledore explained in the note that Lily had sacrificed her life for her son and by doing so had invoked an ancient and powerful magic. As Lily's last remaining blood relative, if Petunia were to take Harry in it would seal the enchantment and provide him with protection from Voldemort.
Dumbledore responded saying that Petunia could not study at Hogwarts due to her being a Muggle and even though he responded kindly, Petunia felt hurt and left out. From that point on, Petunia wanted nothing to do with magic or the wizarding world and frequently called Lily a "freak".
Rowling also explained that Vernon hated Harry for the same reason Severus Snape pretended to: He looked too much like his dad. She also wanted to show Petunia's softer side by giving her a more meaningful farewell to Harry, but had to stick to her unpleasant nature.
As an unqualified wizard who didn't finish his education, Hagrid was not technically allowed to perform magic. And yet, the beloved gamekeeper seemed very magical.
The Dursleys had never exactly starved Harry, but he'd never been allowed to eat as much as he liked. Dudley had always taken anything that Harry really wanted, even if it made him sick. Despite the fact that Harry was often forced to cook for the Dursley's, at Privet Drive, his own plate was rarely full.
All this while, all Dobby has wanted was to warn Harry about Lucius Malfoy's involvement in the opening of the Chamber of Secrets. He wanted Harry to be safe and thus tried his best to dissuade him from going back to school.
And the Dursleys didn't attend the Potters' marriage ceremony. "[Petunia] and Vernon chose not to attend Lily and James' wedding.
Harry and Dudley maintained a relationship:
The once-estranged cousins made amends after Dudley's admission that Harry wasn't a “waste of space” and remained on “Christmas-card terms” as they grew older. However, their relationship never blossomed into a true friendship.
The fan asked the author if Aunt Petunia was a Squib (a non-magical person who is born to at least one magical parent) and Rowling replied: "Good question. No, she is not, she is not a Squib. She is a Muggle.
No doubt Petunia would have been saddened by the news of Lily's death but those complicated emotions – grief, regret and unresolved jealousy – were probably buried in the distractions of housework, gossip and pandering to her son Dudley's every whim.
Her last line there is, "You didn't just lose a mother that night in Godric's Hollow, you know. I lost a sister." Since Aunt Petunia usually prefers not to acknowledge Harry's mother at all, it's a surprisingly sweet moment. In the book, she uses her last words to say "Well — goodbye" to Harry.
Queenie and Jacobs' marriage is a joyous moment for the characters after their victory, but Albus is forced to watch from afar. He's dealing with his own heartbreak. During the battle in Bhutan, Albus had been freed from his blood pact with Grindelwald.
Aunt Petunia was the sister of Harry Potter's mother, Lily, and they didn't get along. The reason for this estrangement actually makes a lot of sense. One of the defining traits of the titular character of the Harry Potter franchise is the fact that the young hero is an orphan.
He has grown afraid of Harry's connection to Voldemort. Perhaps Voldemort, knowing Dumbledore's love for Harry, would possess Harry and provoke Dumbledore to kill him. So, Dumbledore attempted to avoid Harry throughout Book 5 for Harry's own good.
Hagrid appears at the hut and gives Harry his letter in person, leading Petunia to admit she knew Harry was a wizard and that she and Vernon had sworn to stamp the magic out of Harry when they took him in. She claims that her sister's (Harry's mother's) magical abilities made her a freak.
A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to Harry due to his resemblance to his father James Potter, who bullied Snape during their time together at Hogwarts. As the series progresses, Snape's character becomes more layered and enigmatic.
Uncle Vernon and Aunt Petunia (who had secretly longed for magic herself) didn't see much of their nephew, for obvious reasons. Dudley, on the other hand, reunited with Harry a few times so that their children could play together. Their relationship was awkward, but this was a major change from when they grew up.
One of the most beautiful moments in the entire Potter series came from when Dudley and Harry were able to make amends. This occurred in Harry Potter and the Deathly Hallows when Dudley told Harry that he didn't think he was a waste of space. They even shook hands!