The problem with anecdotal evidence
Although it's often accurate--although anybody can write anything on a website or say anything to an interviewer--it doesn't give the whole picture very well, and you rarely get the whole story. I wonder how an emergency surgery for a gall bladder would go uncovered by ANY insurance policy unless there's something more to it.
People, by nature, tend to be outspoken with complaints, and rarely come forward with praise, so the samples tend to be self-selecting.
For example, someone who got excellent health care from their insurance company was very unlikely to wind up in Michael Moore's film.