I recommend any of Matt Taibbi's Rolling Stone articles to get an idea of the type of fraud committed by the Wall Street banks. There may be some minor technical issues with his articles, but they capture the overall corruption.
As for being the world's best bank, let me borrow hundreds of millions of dollars at absurdly low interest rates, give me advanced information on federal reserve policies, and then let me risk that money on the stock market and I'd be rich too. Especially since the too big to fail banks know any major losses will be eaten by the taxpayer. Keep in mind that during the bailouts, the government decision makers were Goldman Sachs alumni.
What did they do that was so bad? How about rigging every market. The LIBOR scandal, gold price fixing, municipal bond rigging, aluminum market rigging, and that's just off the top of my head without even mentioning mortgage backed securities.
All these small fines have done is validate their business model.
