Greed. They wanted to squeeze every last drop out of that company and misrepresented their financial solvency to do so. They created false companies named after Star Wars characters and used that to launder money out of the company to the executives. They were able to pay off in one form or another their auditors that worked for Arthur Andersen.

See, consulting companies had two arms. Accounting / auditing, which caters to public companies that are under the strict supervision by the SEC, and management, which employ teams into their customers' businesses to help run things. These two services were interchangeable but Enron, Tyco, and Worldcom taught us that this was a conflict of interest. Now, we have the Big 4 (PWC, Ernst & Young, KPMG, and Deloitte) auditors who all spun their consulting arms off into separate entities (Accenture, Deloitte Consulting, etc). In addition, Enron and their counterparts' actions lead to the Sarbanes-Oxley Act (S-Ox) which makes the CEO and CFO of public companies criminally responsible if their finances are inaccurate.

We focus so much on what Enron did wrong, that we forget all the employees that lost their jobs, pensions, and 401(k)s and the outsiders who lost their investment.

Did that help you out at all?