There is a wonderful article published on the ABC news website today about how police officers are engaging with 'at risk' youths through boxing.
The title of this post is taken from the article.
I've been working on an article to be submitted to martial arts magazines on courage and fear, and as part of that article I describe how emotion (fear) enables courage through the decoupling of stimulus and response. It is considered one of the most important adaptive features of emotion as it allows other responses to be considered in response to environmental stimuli other than the instinctive response.
That is, it allows us to not punch the fella when our appraisal of the fella elicits the emotion of anger whose action tendency is fight. Courage and restraint are both enabled through emotion which was selected for in nature because it conferred a survival advantage on an individual.