I was a consultant for ten years, not at McKinsey, but a very small firm that actually was ethical by comparison at least, and actually got some good things done, and then later, at another small company that was completely unethical.

In many cases, there was not any question that your job was to justify a decision that had already been made, or attack another group within the company on behalf of whoever was writing you a check. I was literally told on a number of occasions that regardless of what the SOW said, our job was to make whoever was writing the check look good.