How do the errors happen? With appalling ease and regularity. Given that marrying the wrong person is about the single easiest and also costliest mistake any of us can make (and one which places an enormous burden on the state, employers and the next generation), it is extraordinary, and almost criminal, that the issue of marrying intelligently is not more systematically addressed at a national and personal level, as road safety or smoking are.It’s all the sadder because in truth, the reasons why people make the wrong choices are easy to lay out and unsurprising in their structure. They tend to fall into some of the following basic categories.