I'm thinking about when I have to have a hard conversation, for example. I play the conversation in my head many times before I actually get around to doing the thing. And the reactions I imagine are always stronger than what actually happens. I have the whole adrenalin thing going on, feeling sick, voice shaking etc., ready to be shouted at or argued with or walked away from, and it doesn't happen.
By experience I have found that when I face those hard conversations and go into them with the welfare of the other person uppermost in my mind, with emotion set aside as far as I can do that, then the outcome is so much more favourable than I imagined. Indeed, there was a time when I told someone off and they hugged me!
Experience tells me I should face my fears, because they are so much smaller than what I can conjure up in my imagination.