Rodney Brooks on the state of the peer review process for scientific papers:

My three most cited papers were either rejected under peer review or accepted with no peer review.  So I am not exactly a poster child for peer reviewed papers.

If a paper was purely theoretical with lots of equations and no experiments involving processing an image it was much more likely to get accepted than a paper which did have experimental results. I attributed this to people being unduly impressed by mathematics (I had a degree in pure mathematics and was not as easily impressed by equations and complex notation). I suspected that many times the reviewers did not fully read and understand the mathematics as many of them had very few comments about the contents of such papers. If, however, a paper had experiments with real images (and back then computers were so slow it was rarely more than a handful of images that had been processed), the same reviewers would pick apart the output, faulting it for not being as good as they thought it should be.

Those who think that peer review is inherently fair and accurate are wrong. Those who think that peer review necessarily suppresses their brilliant new ideas are wrong. It is much more than those two simple opposing tendencies.

Peer review grew up in a world where there were many fewer people engaging in science than today. Typically an editor would know everyone in the world who had contributed to the field in the past, and would have enough time to understand the ideas of each new entrant to the field as they started to submit papers. It relied on personal connections and deep and thoughtful understanding.