No mention of greed, but Rick's last link quotes Jessica Brady, AAA spokeswoman, with a hint towards speculation:
I'm just skimming over this thread as it grows, moreso because I love to read (albeit, lightly) about understanding the markets. I worked for 3 years in the capital markets area of a home loan lender. I don't know if you can compare the two (home lending/oil), but in the hedge/futures market, we monitored a lot of economic indicators (jobless rates, price of oil barrels, etc) to determine pricing. It seemed like there was a lot of speculation involved. I fully concede your 22 years is > my 3 years, so it is only meant as humble curiosity.