I found a quote that perfectly encapsulates the reason why I've never been able to be much of a conspiracy theorist, especially when it comes to the machinations of government. It's called Hanlon's Razor:
"Never attribute to malice that which is adequately explained by stupidity."

I think this works equally well in the micro-level of personal relationships. I can't tell you how many times I've heard girls concluding that various wrong-doing males were part of a vast conspiracy to shatter their self-esteem, contort their minds, or whirl them into a deadly tango of manipulative mind-games, when really, the guy's just a doofus who hasn't remembered he was supposed to meet you at the coffee shop.