People fail to experiment. Companies make a much costlier mistake when they fail to experiment. Instead of beta testing the idea in some small part of the organization or market place, they do a full blown implementation. An experiment is a trial run. You should be trying to figure out why reengineering isn't for you, why customers won't want your new portable widget.
People fail to get valid feedback.
The whole reason for doing an experiment is to get information about your assumptions and hypotheses. Only accurate, relevant, objective feedback will produce useful information. None of us likes to hear we've failed. You need tough love, not honey-coated feedback. If you don't hear the truth at the beginning, the marketplace will send you the message later, and it will cost you more than a temporary blow to your ego.