I just bumped into this article written by John Siracusa, entitled "Hypercritical". He mainly talks about the over-critical mind and Steve Jobs' amazing use of it. So in defense of over-criticism, here's the articles conclusion:
"The point is, ladies and gentleman, that criticism, for lack of a better word, is good. Criticism is right. Criticism works. Criticism clarifies, cuts through, and captures the essence of the evolutionary spirit…
Okay, let me try that again. Actually, I'm on the same page as Gordon Gekko in one important respect. Like greed, criticism gets a bad rap, especially when it's presented in large doses. It's impolite. It's unnecessarily obsessive. It's just a bummer. But the truth is, precious little in life gets fixed in the absence of a good understanding of what's wrong with it to begin with.
This character flaw, this curse, this seemingly most useless of skills is actually the yin to the more widely recognized yang of creative talent. Is a preternatural ability to find fault enough on its own to make something great? Probably not, but it can help amplify mundane competencies and produce results well beyond what you could have achieved with your creative skills alone."