Its ok to say "I'm tired!". Its ok to want to relax rather than load up and go,unload etc. Its ok to have your fill of working to please the crowd, owners,directors etc. Some guys want it to go on forever, some guys need it to go on forever. It doesn't make anyone any less the performer, musician, or person because they don't want to do it anymore. Dying at your desk, or your keyboard, doesn't impress anybody...or at least me.