You may be selling merch’ after the show and here, smiling is very important.
You make every effort to remain not just good-humored, but warm and gracious.
It comes back to taking care of yourself, then you can remain gracious and good-humored. It’s better to smile mysteriously and remain gracious as you dwell in the inner knowing of your fullness and talent.
Don’t waste your energy getting mad, keep it for your creative pursuits, which are essential to having a strong, separate identity.
Here’s the deal: rolling with your hot muso, you will inevitably spend a lot of time traveling to gigs (think long car rides, airplanes, boats and trains sometimes, frantic taxi dashes), waiting around during soundcheck, running out to get your beloved coffee/tea/whatever during soundcheck. By the time the actual performance begins you may be exhausted from the day and you may not have had the chance to eat anything since breakfast (assuming you had breakfast).
The band may not have either, but they are getting adrenalin from the high of performing and being the main event.
No one else will do this for you because they simply won’t think about the fact that you have needs. Knowing what you are willing and not willing to do means you won’t end up feeling resentful.