What causes people to give up?

Juniors sister wanted to be a writer and write romance novels. She was really smart, smarter than Junior but she lost her hope because something changed her mind and made her think that she couldn't do it or wasn't good enough. Now she is a basement dweller without any hope to do anything. Some factors that cause people to give up is that they don't have self-confidence if they don't have confidence then they well never be able to accomplish anything because if they don't believe they can then no one will. Another thing that causes people to give up is that it is out of there comfort zone. This cause people to give up because they aren't comfortable following their dreams they are uncertain of what is going to happen so instead of following there dreams they give up.