Did you hear that the number one fear of most human beings, in most cultures, is public speaking? Not death, chronic pain or falling from high places. It's getting up before an audience and talking.
Now imagine if that audience had been drinking, had paid admission to see you and you are obligated to make them laugh. A nightmare for some, but there are many brave souls who volunteer to get up there every night, sometimes for free!
Jerry Seinfeld started out that way and so did Danielle Williams who, now at the beginning of her career, is answering the question, "What's it like to be a stand up comic?"