Lust can take many forms. Stereotypical but true, it would be hard to find more than a handful of women who hadn't longed for a particularly fetching pair of shoes or other frippery on occasion.

As for men, one need look no further than the swimsuit edition of a popular sports magazine or the covers of various lad mags and other even more risqué publications that grace the newsstands.

That particular facet of lust was so vexing in centuries past that it was widely believed the afflicted would suffer greatly in the afterlife.

That facet of lust often does contribute to debt -- a contemporary hell -- in the modern day.

"Pornography is a very large industry, but it is hidden," says Stuart Vyse, author of "Going Broke: Why Americans Can't Hold on to Their Money."

"The fact that it is hidden makes it hugely popular because you can engage in it without anybody knowing."

And the Internet has made it very easy for people to indulge with little immediate consequence.

According to Vyse, it's estimated that Americans spend between $10 billion and $13 billion on adult entertainment.

That's a lot of money that might be put to better use in retirement accounts across the country.