I'm surprised that so many people get nervous before their gigs.
I'll admit that in the beginning of my musical career, I was the biggest nervous wreck you ever saw. As a trumpet player in middle school I shook so hard that I literally could not stand, and you still could distinctly hear the trumpet shaking in my hands, against my lips.
Now I've rocked out in front of 10,000 people without the slightest hesitation, making all kinds of bassface and generally looking really weird. When it comes to playing bass gigs, I have absolute supreme confidence.
On the other hand, I no longer shake, but my mouth dries up before a trumept show. This is probably because trumpet is much more challenging to me, as a lead trumpet player, if I miss one of those high notes everyone knows it and I demand perfection from myself. Do you have any idea how hard it is to play trumpet with a dry mouth? It is a horrible destructive thing that makes the situation ten times worse. I end up guzzling buckets of water on stage and having to pee halfway through the show. Not a great situation.
So my ritual before any show is to pee twice, because I drink a lot on stage. No alcohol, though, Root Beer for me, except during the swimming season in which case I cannot drink soda without becoming ill and stick to water.