The GM has to do a lot of the talking. I'm not a good speaker. I have heaps of anxiety that results in giggling when I talk and not breathing. Short version is I'm terrified of getting yelled at. And don't make me sit with my back to the door. That's how PCs get attacked by monsters. Monsters are everywhere! Going to Toastmasters makes me think I'm a little brave. A GM has to get up and talk and this is a fun way to learn how to do that.