The old saw about not comparing your inside to other people’s outside became an old saw because it is TRUE! 
I have been closely observing presenters since the late 1980s, professionally since the early 1990s.  I would make the following observations:
  • If they’re not keyed-up, they are almost always poor-to-dreadful.
  • Keyed-up is not the same as paralysed-by-fear.
  • If they are keyed-up and well-rehearsed to boot, you (the audience) are probably in for a good time.
If you have any doubts about this, charm your way backstage just before the curtain goes up on a professional play; it’s worth the visit – calm, suave, beautiful, highly trained and impeccably rehearsed actors just dying because the curtain will be going up in a few minutes!