Lesson on Public Speaking

I am currently reading the book,"Confessions of a Public Speaker". The author talks about how mistakes happen all the time even with the most experienced public speakers. The good news is the audience in general never cared or noticed any of such mistakes that the public speakers themselves obsessed about. What is considered to be a disastrous mistake during a speech is often the drama in the speakers' own mind. The following is a video of the author showing himself delivering a talk that he considered to have a bad start, a disaster where some slides were missing, where he was making mistakes and he was performing poorly. But just like the author said in the first chapter of his book; I, as an audience, don't care or notice that the talk was disastrous at all.