DISCLAIMER: I don't own anything, JKR does. Good for her.
Have you ever wondered why it wasn't you, Petunia?
Why it wasn't you but Lily? Lily, your beautiful younger sister? Why was it Lily that was a witch, not you?
You always thought that Lily was your parents' favourite.
She wasn't.
You two were just so different.
She was alive, you were dead.
Lily was an optimistic person.
She was always happy, she always had a smile on her face. Well, not on your parents' funeral but that doesn't count.
Lily didn't care about her appearance. That doesn't mean she didn't wash herself and all that but she didn't use make-up to make herself beautiful, she believed in natural beauty.
She was full of life.
She was friendly to everyone, even to people that insulted her. Lily didn't let them get to her.
She was like the sun, when she entered the room, even the coldest person on earth had to crack a smile.
You, on the other hand, took well care of yourself, always in control. But you didn't let your emotions show, you bubbled them up to yourself. You were cold to everyone, you didn't let anyone get close to you.
Anyone except Lily. When Lily was home for Christmas, Easter or during the summer break, you were sisters like before Lily went to Hogwarts. She would tell you stories about Hogwarts, about her friends, about a group of boys called the Marauders and their pranks they had pulled.
But after Lily's third year at Hogwarts School of Witchcraft and Wizardry she started visiting her friens during the holidays or her friends would come over to Lily's place.
That was the year, when you started growing apart. She had her friends and you had yours. Then you met Vernon, started dating him and finally married him.
You hadn't met Lily for almost two years, then your parents were killed and then you blamed Lily for their death because they had been killed by Lord Voldemort, a dark wizard.
On the same day, you found out that Lily had married James Potter, her classmate, one of the Marauders.
Then, you found out that you were pregnant, several months later you gave birth to Dudley and found out that Lily had a little son too.
After a year, on Halloween, one morning you found little Harry crying on your doorstep. When he opened his eyes, you saw that they were Lily's bright green eyes.
Lily was dead and her only son was given to you. You were his Aunt, his only relative he had.
Lily had loved you but you were jealous of her. You were jealous that she was a witch and you weren't. You knew that Harry was going to get his Hogwarts letter and start learning magic. You were afraid Dudley would be jealous of him, like you had been jealous of Lily. So you pretended to hate magic and raised Dudley to hate it also.
It had always been, Lily-alive, Petunia-dead. Now it was the other way around, Lily-dead, Petunia-alive. Though not in the same way.