A successful designer and student of zen, Garr Reynolds delivers a liberating perspective in his 2008 book PRESENTATION ZEN. He knows from experience how much fear of mistakes - or downright earlier disasters - can deter us creatives from thinking and acting out of the box.
His angle on that is "A failure is in the past." As a zen believer, for Reynolds the only time that's real is the now. Therefore, as he points out since the failure was in the past, "In fact, it doesn't exist."
PRESENTATION ZEN is the best guide I've studied which helps us have PowerPoint help clients v making them come across as dull.