She had a husband and son whom she dearly loved, a detached suburban home, two dogs and an enviable job: she knew she was luckier than most and she was grateful. And yet something niggled.
She wasn't sad but, to use her words, she wasn't "superhappy" either. Most of the time she felt mildly harried, her emotional state " just on the positive side of neutral". The sum of the parts of her life should have added up to more joy. But instead she felt in a permanent state of mild distractedness. The house was a mess; she needed to lose a few pounds; she wasn't getting enough quality time with her husband; why did she let petty things annoy her?
It is a feeling many of us will recognise: a vague sense that we are failing to make the most of our existence, that if we could just strive to be slimmer, more giving, have nicer curtains, be more disciplined and perhaps live a bit more like the people we see in the airbrushed pages of OK! magazine, life would somehow be better. So she decided to do something about it; she decided to try to create the 'perfect life'.
Few people can have failed to notice the plethora of self-help books that have blossomed over the past two decades, all promising the same thing - to make you happier; improve your marriage, your parenting, your homemaking skills, your finances, your figure, your attitude, and help you to experience a tangible increase in joy. Niesslein's theory was that if she spent two years following them to the letter, she would get a result.
So Niesslein (35), who lives in Charlottesville, Virginia, bought some self-help books - lots of them - and gamely set about living her life according to their rules and aphorisms. She decluttered her house ('a clean home is a sign of self worth!'), she got completely dressed first thing in the morning and made her bed (a rule of FlyLady, fly standing for 'Finally Loving Yourself') and then she reordered her finances ('Respect attracts money - Disrespect repels money'). Next she conducted relationship exercises with her husband, Brandon, (including saying sentences that began: 'I feel that my greatest contributions to this relationship are ... ') and scrutinised the way she was bringing up her son, Caleb, then six, who was still sleeping in the marital bed, she exercised every day and ensured her cushions were perpetually plumped.
And at the end of the two years, was she happier? Well, cynics, prepare to be smug. Because no, she was not. In fact in some ways she believes that the self-help books damaged her. True, she managed to set up a pension plan, to lose 10lb (she has, she says, put it all back on now) and did take the odd nugget of advice to heart.
But midway through the project she began to have panic attacks. She started to sleepwalk for the first time in years. Niesslein is not a fragile creature but she now thinks too much introspection and self-indulgent navel-gazing can affect self-esteem and mess with your mind. She charts her journey through the world of self help in a book, Practically Perfect In Every Way. Its closing words, meant ironically, are: 'But enough about me.'
"It is a very American idea that you can keep striving and striving and get better and better and better and do it all by yourself by just pulling up your bootstraps. But that doesn't mean it's true," she says.
" I took it too far ... there is a point at which you start losing your personality. You focus on your flaws an awful lot. I started unravelling in the marriage chapter and it got worse in the parenting chapter. You can take analysing your finances and house in an intellectual way but once you get to the core relationships of your life ... it's different. I had this overwhelming feeling that I was just not a good person. I was bad role model. "
Some of the books make you feel as though you really can shape your own destiny when you simply can't, she argues.
One of the things that was causing Niesslein's family anxiety was Brandon's job. He was commuting two hours a day and his employers were laying people off. Whatever the books say, says Niesslein, an individual is powerless to fix job insecurity. It's a fact of life. And yet the impression given is that the individual can remedy all.
"A lot of the relationship stuff promises more than it can deliver," she says. "I think it can be dangerous to a marriage to think the experts know your partner better than you do.
"Some of the things I'm supposed to say to my husband, you just couldn't," she says, laughing.
So why does she think so many millions of people turn so unquestioningly to self-help books? "I think we feel responsible for so much in our lives. There are jobs, kids, the responsibility for your marriage. If you can turn to someone else and they'll tell you what to do, it's comforting."
Niesslein says that she did benefit from those gurus who encourage the reader not to navel gaze but to look outwards at their place in the larger world and do good for others. These included Oprah Winfrey and Martin Seligman, the psychologist and author of Authentic Happiness. One of the best pieces of advice she read was Seligman's idea that one should focus on one's strengths, not one's weaknesses, and the first will compensate for the second.
Cheeringly for those of us who are not life's natural breadmakers, she found that having a permanently pristine house did not bring joy.
Her epiphany came one morning when she was standing in her spotless kitchen, still in her workout clothes having exercised and cooked a healthy breakfast and realised that she had become "the stereotype of an upper middle-class woman who was going about her business as if feminism had never happened. The sort of woman who has no time to work because the day is full of cooking and cleaning and self improvement."
But did she feel even slightly happier? "No. I was busy all the time but I didn't get any fulfilment from what I was doing."
Now the experiment has finished and she is back to her old ways, she is more content. Brandon has a new job that requires less commuting, Caleb still sleeps in their bed at night and she has realised that there is no point buying, for instance, the orange leather couch she covets because the dogs will scratch it.
That is the way her family is and the way she loves them. So what is a 'perfect life?' Niesslein says the definition has changed for her. "I had been envisaging different things, maybe I could be this financal whizz or the life of the party. For a while I thought it was all tied to pleasure. A good life is one where you are basically proud of what you are."
Well, it sounds better than dusting.
Practically Perfect in Every Way by Jennifer Niesslein, Putnam, £11.33