If you’re having a bad day, consider the kind of training Navy SEALs put themselves through, and how they are mentally trained to withstand some really inhuman conditions.
If you have 5 minutes, watch this mental training video from 8 minutes onwards, where they talk about why it’s so hard to go against the fear response (and how they increased their hit rate in getting recruits there).
And read more about it How To Increase Mental Toughness: 4 Secrets Of Navy SEALs And Olympians
As an improviser I watch newbies on stage please audiences by being scared out of their wits. And the improv I love to watch is when those same people understand they can conquer that fear and make great theatre.