(Read more: Who mattered—and who didn't—in the last 25 years?)
These incidents brought ethics to the forefront of business education, and led to an immediate impact on business-school curriculums that would continue to be felt for the rest of the decade and even today.
Beyond ethics, the secondary lesson of Lay and Ebbers was the vital importance for auditors, regulators, and the media to ask questions even when, or perhaps especially when, the math seems baffling or structure and relationships of business entities is incredibly complex.
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Enron was a very complicated company. I remember feeling kind of stupid at the time that I couldn't understand what they did. When the fraud was uncovered, I remember thinking to myself that extreme complexity can sometimes be a warning sign.
This lesson was taught to us yet again in 2008. In describing the crisis, Alan Greenspan noted in his book, "The Map and the Territory," one of the causes as being an "indecipherable complexity of a broad spectrum of financial products and markets that developed with the advent of advanced mathematical models to evaluate risk." Enron and WorldCom were actually the two largest bankruptcies in U.S. history till Lehman Brothers and Washington Mutual overtook them.
I believe there is always a way, with adequate study, to understand even very complex things at some basic level. I never accept "it's too complex to understand" because of the Enron and WorldCom scandals and subsequently the 2008 crisis.
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I think an entire generation of business executives, including myself, was shaped by Enron and WorldCom. When things get too complex, or are portrayed as such, I always raise an eyebrow, and know that with adequate study, there is always a way to understand almost anything at some level. "Indecipherable" is not something that I — or any business executive — should accept.
And so, I think Lay or Ebbers should make the list. Having them on the list will serve as a reminder of the importance of skepticism and digging into the facts and numbers. And, that, while some things are by their nature complex (i.e. certain aspects of math or science), complexity in business can often be a cloak.
(Cast your vote: Who makes YOUR top 25 list?)
—By Jon Steinberg
Jon Steinberg is the president & chief operating officer of BuzzFeed and is responsible for all business management, company operations, finance, and social advertising operations. Follow him on Twitter @jonsteinberg.