Do You Know When You're Going to Blanket a Scene?

A lot of times i'll memorize in the make up trailer. Am, really before, like an hour before. Have you ever had a moment in a movie or a showr on the stage where you just literally blanked, or you couldn't get the line down and you had to do it over and over? Light helps and it helps when you cas it hasn't happened in a minute. But if you're inside your own head freaking out, there's no room for anything special to happen, except fear. And top, it's just awful. The less you care, i think the better, the better off.