Pretty much any cockamamie conspiracy theory is likely to piss me off a little bit, but I'm especially offended by the ones that claim the NASA manned moon landings during the Apollo program were an elaborate hoax. Not only do such hoax theories fly in the face of mountains of evidence that the Apollo landings took place and were 100% genuine, they also display callous disrespect for the people who lost their lives in pursuit of those moon landings. The three astronauts — Gus Grissom, Ed White, and Roger Chafee — who died in the Apollo 1 fire, plus those involved in the program who died in airplane crashes during the 1960s, were a part of something real, a project that sought to do something incredible and unprecedented (and since unmatched in courage and audacity), not to defraud the public and embezzle billions from tax payers.
How rare it is that a government agency is able to accomplish anything, no matter how menial, these days; to think that 40 years ago one was able to land people on the fucking Moon and bring them back home again is a bit incredible. But it really happened. There is an excellent video series posted to YouTube entitled Lunar Legacy that does a good job debunking some of the most commonly held moon landing hoax theories. The synthesized narrator voice gets a little annoying, as does some of the music, but it's mostly a well presented, well argued piece. It's in five parts, all of which I've posted below.
Part Five, which brings it all together and includes some absolutely amazing (and irrefutable by the hoaxers) video footage shot by Buzz Aldrin, of Earth, out the window of the Columbia, on the way to the Moon: