I took a class specifically on this - how company manipulate their financial statements to make things look better.
It's really fascinating. If you're willing to dig into the financial statements (and ones from the past), you can learn a ton about how a company defines "performance" and whether or not it's reasonable.
Despite GAAP accounting rules, there is enough gray area for companies to hide a lot of bad information.
It's pretty interesting to study the mechanism of the fraud. Enron did a lot of things, but one of the big ones was how they booked revenue. Since they were a middleman, they should have booked their cut (i.e. fees) as revenue, but rather they booked the entire purchase as revenue, drastically inflating their growth.
It's really fascinating. If you're willing to dig into the financial statements (and ones from the past), you can learn a ton about how a company defines "performance" and whether or not it's reasonable.
Despite GAAP accounting rules, there is enough gray area for companies to hide a lot of bad information.