Encouraging a fail-fast way of working is a critical element to good agile engineering practice; it is all well and good to say this, but this has to become a real part of the way your business works—as they say, actions speak louder than words. If, for example, we have a manager who thinks that pointing the finger and singling people out when things go wrong is a good motivational technique, it's going to be very difficult to create an environment where people are willing to put themselves out there and try new things. A culture of blame can quickly erode all of the good work done to foster a culture of openness, honesty, collaboration, innovation, and accountability.
Ideally, you should have a working environment where when mistakes happen (we're only human and mistakes will happen), instead of the individual(s) being jumped upon from on high...