Yes I enjoy those days when I'm feeling stronger than what the program calls for and take advantage of that by doing an extra reps or extra sets. Because I know there will be days when I am under the weather and won't be able to do as well so everything averages out in the end.
I don't like to walk out of the gym knowing I still have heaps in the tank but not too beat up either so that fatigue carries over into my next workout. Friday workouts are mad wicked form going balls to the wall because I know I got 2 days off to recover especially after sculling some ep1c and scoop n' half Apocalypse.
I wonder if the Soviets and Bulgarians use the RPE system at all because that goes by feel a lot too doesnt it.