Marjorie Eileen Dursley is the older sister of Vernon Dursley. Although no blood relation of Harry Potter, he has been taught to call her 'Aunt Marge'. Marge is a large and unpleasant woman whose main interest in life is breeding bulldogs.
"The first meeting between Lily, her boyfriend James Potter, and the engaged couple, went badly, and the relationship nosedived from there," Rowling revealed. Rowling adds that Vernon hated Harry because he saw father James in him, much in the same way that Snape does.
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.
The Dursleys were generally neglectful of Harry, but they became abusive when they punished him. For example, the way that Harry had to wear all of Dudley's huge hand-me-downs when the Dursleys could easily afford new clothes that fit Harry, and the Dursleys made him stay with Mrs.
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.
Skip forward eleven years, and it transpired that Vernon didn't handle that situation very well at all – with his unwanted nephew, Harry, confined to a cupboard under the stairs, and always on the end of a torrent of abuse from his uncle, while his cousin Dudley was lauded with praise for being a puerile bully.
Petunia's disdain for Harry was most likely born from a long-standing jealousy of her magical sister, Lily. A Howler from Dumbledore, addressed to Petunia, said 'Remember my last' – no doubt referring to the letter which he left with baby Harry, on the doorstep of Privet Drive.
Specifically, Draco was jealous of Harry. It was easy to miss because Draco didn't often show his emotions, modelling himself on his cold, confident, calculating father, but J.K. Rowling has confirmed that a lot of his enmity towards Harry stemmed from envy.
Petunia was incredibly jealous of Lily's magical ability and hated that her magical sister always seemed to be the centre of attention. When she married Vernon, she didn't want Lily to be a bridesmaid because she was tired of being overshadowed by her.
The aftermath of this saw Dudley change to an extent; he became less belligerent and even civil to Harry. The Dementor attack was the catalyst for a change in Dudley's personality that started in Order of the Phoenix, and we saw the end result in Harry Potter and the Deathly Hallows.
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.
His last words in the movie are, "I still don't understand why we have to leave." But he also has a deleted film scene where he has a final conversation with Harry, and his last line is, "I don't think you're a waste of space." In the final book, Dudley's last line is simply, "See you, Harry."
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.
But Rowling states that as for Vernon Dursley—true to form—he hated Harry for much more human reasons: he felt embarrassed by his father, James Potter, who Harry uncomfortably reminded him of. Rowling wrote that when Vernon met the Potters, James was amused by Vernon, and made the mistake of showing it.
Harry also made very strange things happen to the Dursleys whenever he felt strong emotions. And since the Dursleys loved being normal, anything out of the norm from Harry was considered bad behaviour. So they thought that he was a generally misbehaved kid.
Isaacs brings up Lucius' disheveled appearance in Deathly Hallows, raising the possibility that the Malfoy patriarch had begun drinking too much. The way Isaacs saw it, Lucius was in a no-win situation. Given everything he'd done, the man no longer had a place on either side of the war.
Draco had several reasons for lying to Bellatrix, including the fact that he was never a bad person. Moreover, he no longer found working for the Dark Lord appealing and hated how Voldemort treated his family. He did not intend to harm anyone and believed Harry was the only person capable of defeating Voldemort.
“Harry was constantly crushing on Draco. He just couldn't hide it.” In the books and movies, Harry and Draco are constantly at each other's throats, given that Draco's parents are Voldemort supporters and the evil wizard killed Harry's parents.
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.
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.
Harry was supposedly on amicable terms with the Dursley family, claiming they were on his Christmas card list. Uncle Vernon and Aunt Petunia (who had secretly longed for magic herself) didn't see much of their nephew, for obvious reasons.
He spent the rest of the summer with Ron's family and did not see the Dursleys again until the summer of 1993. Harry sadly managed to get on the wrong side of his relatives within the first week of his return to Privet Drive.
In the “Potter” books, Harry's parents are killed by the evil wizard Voldemort when he is an infant and he is taken in by his aunt and uncle. However, his aunt and uncle mistreat him, including forcing him to sleep in a cupboard and denying him food.
He didn't care for Harry but he understood that Harry needed care. (This is important: because as humans we don't have to love someone to help them). The Dursley's didn't just abandon him at home when they left for their social activities: they left him with Mrs. Figgs.