I guess I'd take a somewhat contrary view and say we all have a responsibility to educate ourselves before undergoing any medical procedure, but "educating ourselves" is not the same thing as "listening only to everyone who's had a problem." It IS, however, understanding how often problems happen, and how severe they're likely to be, and weighing those risks realistically against the risk of what might happen without the treatment, or with a different treatment.
Like Helene, the problems with LASIK you read about - yes, those problems can be severe and life-altering for those who have them, but it makes a big difference whether those problems happen to 0.5%, 5% or 50% of people who undergo LASIK, and that's the kind of thing you can only find out by poring over medical journals and making sure your research isn't limited to industry-sponsored studies, which are even more misleading than limiting your research to support groups for people who have had severe complications. Understanding statistics helps weed out studies that were poorly designed, or that were designed to yield information other than what you're looking for. Checking a journal's history of retractions helps get a sense of how rigorous their peer review process is.
We can't trust doctors to tell us the whole truth about the likely consequences of treatment or the course of recovery - as Pax recently found out. The existence of people with severe complications doesn't tell us anything about the likelihood of those complications (though sometimes, those support groups offer links to research). We have to do our own homework.