There is only one thing which can master the perplexed stuff of epic material into unity; and that is, an ability to see in particular human experience some significant symbolism of man's general destiny.
As a teacher you are more or less obliged to pay the same amount of attention to everything. That can wear you down.
I mean, I really liked those guys and the experience of doing Raiders was really good for me, but I did not really want to be involved - I only did Jedi, as I really owed George a favor.