When I was acting, I got trained in creating a character as a three-dimensional person. If you're doing it right you should be able to draw an audience into the character's world and make them feel their fears.
I thought I could never write a proper book; I'd never done it before. But I thought I could write a sequence. Then I had a chapter. The next thing I knew I was turning acting down.
With acting, you have to depend on somebody else to decide if you are allowed to work. You can spend weeks and months when you are not acting at all.