Kirk:  You are in error. You did not discover
         your mistake.
Kirk:  You have made two errors. You are flawed
         and imperfect and have not corrected by
         sterilization.
Kirk:  You have made three errors.
Nomad: Error. Error. Error. Examine.
Kirk:  You are flawed and imperfect! Execute your
         prime function!
Nomad: I shall analyze error. Analyze ... error ...

Here is a very good explanation of how a lack of understanding
of math and probabilities brought Lehman Brothers (and a lot of others)
down.

I especially like this analogy.

There is also a second and more subtle source of
error. Whether you can make money from selling the
CDO insurance for the bank depends on whether the
borrowers return the money, which in turns depends
on the economy. So if the economy goes down, you
are a lot more likely to lose money. If you are an
active investor, then you probably have invested in
the stock market as well. Now if the market crashes
you lose both the money invested in the stock
market and in the CDO. Suppose, on the other hand,
that instead of spending the money on CDO, you bet
on whether Manchester United will win the European
Champion League. This time in order to lose all
your money you need both the market to go down and
Manchester United to lose their match - this
is less likely than just having the market go down.
Therefore, investing on CDO is a riskier choice
than betting for Manchester United. The error in
our model is that we have not taken into account
this extra risk due to its dependence of CDO on the
market.

Or the NY Mets, if you prefer.

C