Speaking of bullshit, that's kind of what this show is. Not that it's bad-- it's good entertainment. But less critical viewers will need to be reminded that it's entertainment, not thorough scientific research.
While Penn and Teller do sometimes offer scientific research to bolster their arguments, the tend to present it in a manner that contradicts the purpose of serious investigation. I take issue with the way they enter their investigations with the assumption that something is "bullshit" and how they subsequently mold every piece of information that becomes available to them to reinforce their pre-determined conclusion. A real investigation would not involve them going into their research with the determination to prove it a fraud; it would involve a suspicion which they either prove or disprove after careful examination of the evidence.
I feel that the show manipulates your judgments by doctoring evidence, cutting and pasting phrases out-of-context, repeatedly showing loaded footage, making dismissive commentary without backing, relying on 'straw men' to win arguments, calling people "assholes" for having differing opinions, creating irrelevant "experiments" whose outcomes, at first glance seem to corroborate their point, but upon re-assessment, are not logically congruous with the evaluations you will make based on them (in other words, the experiments are misleading).
P&T essentially bully the viewer onto their side by creating an atmosphere in which you will feel dumb if you disagree; their ridiculously biased presentation ensures it. I'm not saying that most of the stuff they take on isn't bullshit, but their methodology is more akin to "Inside Edition" than, say "BBC News"; it's like a sloppy email forward, filled with ad-hominem attacks and hot-headed rhetoric, not a well-researched feature article. If it seems funny, well-intentioned, and consumer-advocatory, it is; but it's also manipulative and intellectually dishonest, at least for something that you given to understand is an unbiased documentary. That, in and of itself, should be a good reason to watch with caution if you're trying to get anything out of it besides entertainment.
