EconLog, An Economist’s Guide to Happier Parenting, Bryan Caplan: Library of Economics and Liberty

Happiness research hits a lot of nerves, but the finding that kids don’t make people happier may be the unkindest cut of all. As a proponent of having more kids,
I could make methodological objections, but the truth is, I do notice a
lot of people who don’t seem to enjoy being parents. My view, however,
is that to a fair degree, these parents just aren’t doing it right! Fortunately, basic economics is here to lend a helping hand.

My main observation about parental unhappiness is this: The last 10%
of parenting hours causes half of all the parental unhappiness. First
two hours with your kids: a joy. Second two hours: pretty good. Hours
5-8: Tolerable. Hours nine and ten: Pain. Remaining hours: Anguish.
There are few better illustrations of the law of diminishing marginal
utility.

Once you see this clearly, there are some obvious solutions…