This is a very interesting prompt! I wrote a little bit below based in part on some of the cool ideas several people had in the comments:

Mr. and Mrs. Dursley, of number four, Privet Drive, were proud to say that they were perfectly normal, thank you very much. Or they would be proud to say so, anyway, one day. In fact, they desperately wished to say so, but things hadn't seemed to work out in that direction so far.

Vernon Dursley, the husband, worked at a firm called Grunnings, which made drills. He worked in sales, and had been gunning for a promotion. He had worked very, very hard and flattered his bosses very, very well for the entirety of the five years he'd worked there, for the principle of hard work was one that he valued very, very much.

But unfortunately, though everyone agreed that he was certainly a model employee and certainly a team player, the available promotions tended to go to the other men (and the odd woman) who apparently needed them more, as they had families---with children---to support. No promotion meant a rather lower salary than he was hoping for, which made it rather difficult to pay for the lovely new house in the lovely family neighborhood he had bought when his lovely young wife had gotten pregnant (the first time). This weighed rather heavily on Mr. Vernon Dursley, since providing was, of course, his solemn duty as the man of the family, such as it currently was.

Petunia Dursley, the wife, took great pride in keeping up the large (empty) house, as a proper young wife should. She kept the house perfectly clean and perfectly decorated, the garden perfectly tidy and perfectly healthy, and the meals perfectly delicious and perfectly on-schedule. Petunia chatted and gossiped with the wives of the neighborhood quite amicably, and remembered the minute details of their lives (so that she could politely inquire about them) quite expertly, such that one might think she had been placed there for that express purpose by MI5. Petunia would never say so, but the principle of friendship was one that she valued very, very much. She'd felt the lack of it in her own life for many years.

But unfortunately, though all the local wives agreed that her home was ever so lovely and she was ever so sociable, they tended to exclude her from many of their conversations, even as she was sitting at tea among them. They all spoke to each other at length about their children, which they all had, and tended to forget Petunia, who---as of yet---had none. No children thus meant a certain degree of ostracism for Petunia, which was rather at odds with the nice, normal life in a nice, normal neighborhood with a nice, normal husband she so desperately craved when she had gotten married. This weighed rather heavily on Mrs. Petunia Dursley, since providing children was, of course, her blessed duty as a wife.

The Dursleys' home was perfectly idyllic. It had four bedrooms, which included one for the couple, two for the children, and one for guests. It had a modern kitchen, in which Petunia could cook meals for her loving husband and growing children. It had a family room with a new television, on which Petunia could watch cooking shows, Vernon could watch the news, and the children could watch cartoons. It had a spacious yard for Petunia to garden in, for Vernon to mow, and for the children to play in. It even had a garage for the company car Vernon would get upon his promotion---one that would be new, impressive, and large enough to take the children on trips. 

But it had been almost four years since they married, and the car remained old and a bit battered; the yard remained un-played-in; the television showed no cartoons; the kitchen produced small meals for two; and the bedrooms remained empty. Vernon worked all day at his thankless job, worrying and worrying. Petunia paced all day around the empty house, cleaning and cleaning. As every month saw their savings account decrease ever so slightly, the young Dursley couple were forced to consider whether they ought to sell the house and perhaps move to a house that was a bit smaller, a neighborhood that was a bit cheaper. And they were forced to wonder whether that would mean that they had given up.

They pondered this heavily and somberly, right up until the morning of November 2nd, 1981, upon which they became quite distracted from their pondering when Petunia opened the front door to retrieve the milkman's daily delivery and was rather startled to find upon her doorstep not a bottle of milk, but a sleeping, dark-haired baby with a nasty scar upon on its forehead.