There is the gig, of course that goes the other way. The realization that you dont have the right gear, amp, etc for the project. It can work both ways.
Your fourth sentence proves your third sentence false!
the more I play the same stuff, the less I want something else, particularly if I'm taking the time and effort to keep the stuff I'm playing setup and maintained properly, and really practicing a lot. It makes me focus on the music and my hands and not the gear. Also it makes me pickier and realize how hard it is to get something else tweaked up to par, and If I'm playing a lot, I'm more sensitive to differences that make it impossible to play the harder stuff I'm trying to play.
A new Hardtail Strat would be Nice!