This, Mr. Calder argues, made the message of the movie “more wrong than right.” Mr. Ham himself came to realize as much in the years that followed. By 1916, he had teamed up with the better elements of the lending business to pass laws that set a standard rate of 42 percent — an eye-popping rate by today’s standard but, at the time, still progress. “It was the birth of the modern personal finance business,” Mr. Calder says.

It’s easy to see everything since then as a step in the wrong direction, to romanticize a time when debt was less common. But think about what life was like before easy money. Think about how hard it would be to buy a house or pay for college if a 42 percent interest rate still seemed normal.

Some of the changes are surprisingly recent. Just a generation ago, a temporary setback, like illness, divorce or job loss, was much more likely to force a family to take drastic measures than it is today. That’s in large measure because of debt, which allows families to smooth out the rough edges of their financial lives.

You can see this change in the national statistics on consumer spending. Since the early 1990s, the peaks in spending growth rates haven’t been as high as they were in the 1960s, ’70s and ’80s, but the valleys haven’t been as low, either. Not coincidentally, recessions have come less often over the last two decades and they have been fairly mild.

Mortgages are a big part of this story. Thanks to the enormous amount of foreign capital that has flowed into the market over the last decade — the same influx of capital, yes, that helped cause the boom to get out of hand — the mortgage business has become bigger, more competitive and more innovative.

If you take out a mortgage today, you’ll pay thousands of dollars less in upfront fees than you would have in the mid-80s. (Those fees have fallen by 80 percent in just two decades.) Home buyers who know they’re going to live in their house for only a few years now also have the ability to get an interest rate that reflects their situation. The 30-year fixed-rate mortgage isn’t the only game in town.

Of course, people in the mortgage business — the brokers, lenders and Wall Street executives who brought you the meltdown — like to argue that the current problems are mere footnotes compared with all the progress. They are wrong about that. The excesses were real, and they were big. We’re still figuring out just how big.

The solution will have to involve new guidelines, voluntary or government-imposed, that force lenders to be clearer about the terms they’re offering borrowers. But as long as we take tough measures to clean up the mess, we’ll end up with a healthier mortgage market than we had beforehand. And then we can go looking for the next form of debt to captivate and torment us.