If you’ve failed FAR before… why?

I’m curious what your experience was after failing FAR. Especially for those who thought they did everything right during their study sessions. Everyone says most people fail FAR at least once. I don’t want to set back my schedule and pay more money for a retake. What do you think was your hang up for not passing first try? Was it just nerves or not having a good grasp on a certain concept? Maybe both?