I used to belong to the “what’s wrong with you people??” school of personal finance advice.* I found it hard to sympathize with people who carried credit card debt or failed to save for retirement. Surely they knew better. So why didn’t they do better?

Turns out there are a lot of reasons, including the economic forces that have squashed so many households: stagnant incomes, high unemployment and a changing economy that scrapheaps many less-educated workers. Getting ahead is getting harder, with economic mobility in the U.S. now trailing most of Western Europe, including traditionally class-bound Britain.

Scientific research points to a number of other causes. A study of Swedish twins indicates there may be a gene for responsible money management–and most people don’t have it. The way our brains are wired also works against us. The field of behavioral economics tries to explain why we so often do what we shouldn’t, and don’t do what we should.

I wrote about some of these issues, and what you can do about them, in my latest DailyWorth column: “Are biases and beliefs keeping you from getting rich?”

Faulty programming doesn’t give people a pass. If you don’t save and run up debt, you’re going to have a lot of stress now and an impoverished old age later. But knowing about the science and psychology of money mistakes could help you reprogram yourself. And this knowledge should help those who are “good with money” be a little more sympathetic to those who aren’t.

*Okay, on my bad days, with enough provocation, I can still give away to exasperated disbelief. But I’m trying to be kinder.