The Rest action requires you to not be at max energy, but that's a detail which I shortsightedly looked over. A mouseover tip would've been helpful, but since I probably won't work on this game again, giving more details will probably be something I'll improve on in the future.
Yes, the game is kind of a grind (and other people have pointed this out too), but that's probably yet another bad design decision I made and nothing I can really do now.
Thanks for playing the game though, I hope it wasn't too bad of an experience.