We can add to this, "when performing, just play."
I have a wonderful recording of Elgar's Enigma Variations with Solti and Chicago. Besides the wonderful moment in Nimrod where the brass prove they can play louder than anyone else in the world, there is not only a wonderful sense of "hey, this is easy!" but especially an attitude of "hey, this is fun!"
We tend to be our own worst critics--which is good for personal practice, but it is an attitude we need to shed when we step on stage. At our best, we are ready and eager to go; at our worst we are afraid we are going to sound like someone trying the trumpet for the first time.
At such moments, my best advice (to myself, too) is simply to fake it. I'll pretend like I really can play the piece that I have practiced, and it usually comes out wonderfully; the inner critic is silenced, and I can have fun!
Not only weird, but complex is the Vulgano mind.