If you see only one more movie this decade, make it Adam McKay's "The Big Short." If you see only one more movie in your lifetime, make it this movie. If you are reading this financial column, investing two hours of your time and the price of admission into this movie may be the best investment you ever make."The Big Short" is based on Michael Lewis's book by the same name and is adapted for the screen by McKay and Charles Randolph. Lewis is a celebrated author in financial circles known for many Wall Street bestsellers including "Liar's Poker" and "Flash Boys." What separates "The Big Short" from all other Lewis works and makes it prerequisite viewing for any investor is access and accessibility. "The Big Short" continues on Lewis' theme of exposing the hidden side of Wall Street, but what makes the movie the best adaption of his works is that the topic at hand is so easily accessible to viewers. The underlying theme and the spark that ignited the ensuing Great Recession was, simply put, unbridled greed. Specifically it is unbridled greed in trading mortgage backed securities. This is what makes the movie so accessible to everyone, buying and selling a home is a person's largest single transaction during their lifetime.The movie lets us, the lay-investor, in on a few of the darkest secrets of Wall Street. Perhaps the most important of "secrets" that has since largely been addressed is that Wall Street was/is largely pay-to-play. In an important scene in the movie (spoiler alert), when traders who have discovered the impending collapse of the housing market confront an acquaintance at credit ratings agency Standard and Poor's (S&P), she admits that inflating ratings on securities is the name of the game. If her agency does not give a customer - a large bank who bundles mortgages - the rating they want, the customer will simply go to Moody's or Fitch, the two other large credit ratings agencies. The takeaway: Ratings agencies' ratings are only as dependable as the agencies are trustworthy.In another important scene, a college buddy-turned-journalist of one of the other traders who is shorting (betting against) mortgage backed securities is presented with the massive fraud that the traders have uncovered. The reporter for The Wall Street Journal is told that banks who packaged these now toxic assets are immunizing their balance sheets by selling the securities. The same banks then join these traders on the short side of the market, betting that the very securities they packaged will fall in price. The Wall Street Journal journalist declines to write an article, saying he has a family to take care of and cannot risk losing his job by printing the allegations his friends have brought him. The takeaway: Journalists have a vested interest in not printing news that will hurt their friends and those that advertise their papers - in this case, the news being, hiding massive fraud perpetrated by the major banks and ultimately ripping off the American taxpayer.So, what can "The Big Short" teach the average person about investing? The primary lesson learned needs to be that flashy websites, stock exchanges, financial news networks and data terminals cannot replace common sense. If the numbers flashing on the screen of your computer do not reflect reality, be weary. Another important lesson is when the lines between the aforementioned actors and government agencies are permeable and regulators can join the very banks they regulate and return to regulating other financial institutions, conflicts of interest will arise. This need not be fraudulent; regulators and bankers are all people, and may favor those who they have built relationships with. Governments need to ensure these types of conflicts are limited through thoughtful legislation.Finally, if you are wondering whether these types of "doomsday scenarios" are possible in Turkey, rest easy. Commenting on the mortgage crisis, Omer Paksoy, the chairman of Turkey's largest mortgage broker, Hesapkurdu.com, said: "Turkish markets are not prone to such vulnerabilities due to the fact that the secondary market is non-existent. Therefore, banks hold all of the loans they underwrite on their own balance sheets and carefully monitor underwriting criteria."Go see "The Big Short," you will not regret it.