Saturation point

Is it possible... if you have had a REALLY productive and busy day, getting many of your items checked off the "To Do" list and many loose ends tied up on projects and teaching your classes and having really good rehearsals, that at the end of the day when you have an unexpected block of free time, you don't know what to do with it and you end up just sort of wandering around saying "what now?".....that your brain has reached a saturation point and you just need to pack up and go home?