Fail fast because life is short and you don't want it to be one prolonged, slow-motion train wreck.
It seems to me that one big problem in life is that successful communities depend on improbable actions. How many athletes tried for a gold medal in each event? Dozens showed up in London but before that there were hundreds at national qualifying rounds and before those, thousands or millions who aspired to greatness in regional meets. We don't get our heroes without first inducing thousands of "losers" to participate.
The same is true of scientific advances, business start ups, careers in acting, art, writing, comedy, and politics. A community that advances by running faster, making things cheaper, creating new products we suddenly can't live without, art that moves us, dance steps that make us all get out of our seats, or stand up that makes us laugh hysterically gets there on a road strewn with failure.
It seems that the communities that do this best don't just reward the winners (it's important for aspiring novelists to know what kinds of books critics and book readers want). They also encourage the losers (lots of great breakthroughs come from people who lost the first time, and the second time, and the third ...), take some of the risk out of losing (given the high probability of losing, we want the simple act of participating to have its own rewards, whether it be the great physical condition of competing in sports or the incredible learning that comes from trying to start a business), and give people room for reinvention after their losses.
The more that failure is treated as feedback rather than affirmation of our worst fears, the more it can be used to guide us. The world we live in is changing, we're changing, and our understanding of both is wildly incomplete. And we've never needed more experimentation than now, more desperately needed people to go off script.
After all these obvious claims comes the big question. How does a community encourage people to take improbable risks? I'd argue that it comes at least as much from making loss palatable as it does from making victory that much sweeter.