Lesson number 1 -
If you screw up, it is your problem. If you screw up big time, it is your boss's problem. If you screw up really well, big time, for a long time and make a lot of money in the process, the US Fed will take care of you.
Lesson number 2 - Greed is always good.
Have a look at the news article below, and then take a look at the ad which captures the essence of the "sub-prime" mess brilliantly..