This is Millican’s Law. If you have a hard gig, quiet, a death, a struggle, whatever, you can only be mad and frustrated and gutted until 11am the next day. Then you must draw a line under it and forget about it. As going into the next gig thinking you are shit will mean you will die.
Equally, if you nail it, slam it, destroy it, whatever, you can only be smug about it until 11am the next day (in the past, I have set an alarm so I could get up and gloat for an extra half hour) as if you go into the next gig thinking you are God’s gift to comedy, you will die. That is Millican’s Law and it totally works. It means you move on quickly.
Hope it helps. It’s certainly stood me in good stead.