Wood's Law of Conspiracies
Conspiracy theories have gained a wider audience now that they travel at the speed of the Internet. The vast majority of these "theories" are convoluted enough to make Eraserhead seem straightforward. After factoring in a typical human's inability to keep a secret, and the fact that perfect henchmen only exist in Bond films, there is a much simpler explanation possible:
Never attribute to conspiracy what can more easily be explained by laziness or incompetence.
I coined this several years back and though it was about time to put it out there.
Further reading: Conspiracies and Wishful Thinking by David Brin (one of my favorite authors.)