For those of you directed here by a skeptic you're arguing with, this is what I mean by "woo." It encompasses pretty much everything typically labeled "supernatural," psychics, alternative "medicine," free energy/perpetual motion, religion, denial of well-supported science, giant conspiracy theories, etcetera.
One of the things that always, always irritates me is when some woo follower describes the skeptical stance on some issue of woo. I've never seen one get it right. The dominating causes seem to be: 1) Outright lying (usually done by Big Altie corporations, and any woo selling a book), 2) Parroting someone from category 1 without bothering to listen to the real skeptics they're engaging hit-and-run trolling with, or 3) Complete inability to parse a sentence.
So, for those of you in category 2 and 3, I'll try to make it clear to you in this post what our problem is. I consider myself fairly typical for a skeptic, since I see a lot with similar views.
First: I do not label anything "impossible," except for logical and mathematical impossibilities (click here for explanation of that). For stuff like free energy machines that violate the laws of thermodynamics, I only use "impossible" in a implicit conditional: "That's impossible if the laws of thermodynamics are right."
In other words, if the machine works under controlled conditions (AKA "No cheating"), then it means thermodynamics is wrong. That's a very big claim, so we need very good evidence before believing that it's true. Interestingly enough, it's usually the woos labeling things we can observe and repeat countless times as "impossible." They're often quite willing to put limits on the physical universe for no reason.
Second: I'm perfectly willing to give the woo a test. The problem is that woos typically don't understand that we are very picky about bias. That's why I don't consider taking alternative medicine myself a meaningful test, or inherently cherry-picked anecdotes as useful: I'm biased, you're biased, we're all biased, and the alties never bother to take that into account. Double-blind control studies are the gold standard because they're designed to eliminate bias: If a person doesn't know if he's taking the real thing or the placebo, he can't easily influence the results. A number of woos still somehow complain that the test can be biased, but they never seem to point out how the bias can slip in.
Third: I'm not raging against anything "new", I'm raging against old, broken stuff with new coats of paint and how people use it to hurt others. Even more irritating are the people who defend those nasty people with thought-stopping clichés, rather than just spitting out solid evidence that they're really helping people.
The most subtle, and probably most dangerous effect woo has on people in the long run is isolation against new ideas. New ideas often mean that old ones can be wrong. Skeptics embrace that. When woos refuse to subject their ideas to a test that could prove them wrong, I see a whirlwind of genuine closed-mindedness and rejection of progress. Quite frankly, I see a lot of psychological projection on the part of woos: They accuse skeptics of being mean, isolated, miserable, and old-fashioned when I tend to see woos exactly like that, given the typical trolling.