"The problem with Occam's Razor is that you can't actually cut someone with it."
I have an issue with conspiracy theories. The issue is not so much that they exist (that would seem to be an inevitability, especially in the age of the internet), but that I have repeatedly seen otherwise intelligent, rational people become completely drawn into these theories without ever apparently noticing the faulty logic and massive confirmation bias required to sustain such ideas.
I can see the initial attraction that some of these ideas hold. They form a gateway to a world full of mystery and intrigue, where covert Government agents fly the disguised Roswell spacecraft into the twin towers whilst Illuminati Reptilians fuck JFK to death on the set of the faked Moon landings. Or something. While it may seem more exciting to live in a real-world version of Deus Ex, the problem is that there is no significant quantity of reliable evidence that can back these claims up.
Which is not to say that there are no such things as conspiracies. They happen all the time, but the key point to note is that they are all relatively simple as far as the relationship between effort and payoff goes; Guy Fawkes and his companions plotting to blow up the Houses of Parliament, industry executives paying experts to mislead the public about the nature of their product, or even a group of friends planning a surprise birthday party. What is clear in each of these examples is that there is an obvious and simple motivation for engaging in the conspiracy, a clear and not overly complicated solution for achieving an outcome, and a reasonable amount to gain from success.
If you take a popular modern conspiracy theory (9/11 Truth, or faked moon landings for example), you will tend to find that these things are conspicuously absent. Why the US Government would wish to stage a "controlled demolition" of an important landmark and economic centre, killing thousands of citizens in the process, is unclear. Their supposed methods for achieving this, and the various ways in which they are supposed have "covered up"* this attack are convoluted and bewildering. It could reasonably be said that what they gained from all this was a pretext upon which they could invade Iraq, but given that it seems fairly obvious that they were already going to invade anyway, and the flimsiness of the pretext upon which they did eventually invade, it seems a fairly outrageous suggestion that they would go to such confusing lengths to do it, including attacking their own military headquarters in the process (I'd have thought it fairly important to have an intact, functioning military HQ if you're planning military action). Add to all this the constant shifting of goalposts and absurd requirements for the evidence that would convince them that the accepted version of events is closest to the truth - take, for example, the refusal to accept photographs of debris outside the Pentagon as containing aircraft parts, despite, well, obviously containing aircraft parts.
What this all boils down to, is that none of these conspiracy theories are actually proper, functioning theories. A decent theory takes all the available empirical evidence and unifies it into a well thought-out explanation. Whereas your average conspiracy theory will take the issue and tear into it, raising question after question after question that requires explanation. Their version of events then seems to be taken as a de facto answer to these questions, without actually having any evidence to back it up.
Now, I'm not saying that the standard explanation of events should be unquestioningly accepted, but it is important to go where the facts lead you. Having an open mind is a virtue, but it shouldn't be so open that your brain falls out.
* Although it can hardly be considered an effective "cover-up" if a fourteen year-old with a YouTube account and a webcam is able to "expose" it.