The Worst-Case Scenario

I understand that one way your self doubt manifested was that you were worried about mis speaking in class, saying something wrong. And i'm wondering, when you imagine making a mistake like that, what was the worst case scenario that ran through your head? You've been a professor for a while now. You clearly know what you're doing. But theye are some days when i find myself doubting whether i have the expertis to be ablet o speak in front of people. So i do still have those experiences.