I once did some consulting for a very prominent bond fund manager. His main tool was an excel spreadsheet which was the most godawful mess you can imagine. Dozens of separate pages with tens to hundreds of thousands of cells each. I ended up writing some VB code to dump all the formulas into a text file where I could parse them and do some automated analysis (using Common Lisp). It turned out that the spreadsheet was in fact as much of a train wreck as it appeared to be. Most of it turned out to be dead code, i.e. >50% (I don't remember the exact number) of the cells did not figure into the final result.

But the worst part was that there turned out to be a single input that completely dominated the final result, and that input was a "gut feel" that the fund manager had about which way the market was going to move. So after all that calculation, the upshot was that the fund investment decisions were being made based on this individual's intuitions, and the entire spreadsheet was just window dressing. Ironically, the audience for the window dressing was the fund manager and his team because the spread sheet was considered proprietary, a closely guarded secret. That's the reason I'm not revealing the name of the manager. I'm probably still bound by the terms of the NDA.

That was the moment that I realized that much, if not most, of Wall Street is a colossal scam.