What’s the worst thing that can happen to you as a speaker? 

Having the  audience get up and leave during your speech would certainly be a bad  thing, but since there is very little chance of that actually happening  perhaps we should focus on things that are more likely to happen to you.  Like completely forgetting your speech as you stand there on the stage. That can happen to anyone at any time. 

If it happens to you, what should you do?