I feel like my papers are better for having gone through peer review, and I'm a better researcher for having had a few rejections. Of course the reviewers can't hover around in your lab watching everything you do. But even if reviewers can't check the validity of the evidence in your paper, they do a pretty good job ensuring that the claims you make are supported by the evidence you present. That's a valuable if imperfect guardrail! What would be the alternative?