I actually think it's those that get so close to the truth, before veering to the right and blaming minorities instead of those who are really to blame (by design of those who are really to blame, of course) - blaming Jews for controlling the banks and the media (it's the obscenely rich), blaming immigrants for poor work conditions/no jobs (it's the obscenely rich), blaming disabled people for being a burden and leeching off the tax payer (it's the obscenely rich), blaming whichever generation is currently in young adulthood for "destroying industries" (it's the obscenely rich), and so on and so on..
I guess they make me angriest because the truth clearly isn't outside of the people who believe the conspiracy's grasp, they'd just rather punch down, solve nothing, but continue to have minor feelings of superiority (which really ties in with the key to all belief in conspiracy theories - "I have special knowledge you don't"), than punch up and actually try to resolve the issues they whine about..