A little fear of public speaking is good, but a lot is awful

Is public speaking fear good for you? Maybe yes, maybe no - as is shown above. It depends on the level of fear. An article by Dean Burnett in The Guardian on October 16, 2014 titled Social anxiety: why the mundane can be terrifying pointed out that:

“....Sometimes, stress and pressure can increase performance. 


This is actually a reliable occurrence, and gave rise to the Yerkes-Dodson law. This law can be represented by a simple curve, and basically shows that as nervousness and stress increase, performance increases. 

 
You’ve heard people say they work better when a deadline is imminent? This is probably true. And maybe the brain is piling the pressure on in social situations where you want to impress – to increase your performance, upping the odds of you doing so?
 
But this increase in performance only occurs up to a point. And that point is all important: too much stress or pressure and your performance declines to nothing. People can’t function properly when they’re incredibly stressed, and it shows.”

That curve also has been discussed in a 2011 article by Jennifer K. Paweleck-Bellingrodt on Anxiety, a 2012 article by Scott Duggan titled You Need Stress - Really! and a 2015 article by Till H. Gross titled 4 public speaking tips from a professional public speaker. A more detailed 2012 article by Dan Goleman at Psychology Today discussed The Sweet Spot for Achievement - what’s the relationship between stress and performance?