You have to master not only the art of listening to your head, you must also master listening to your heart and listening to your gut.
Unlike some of the time-travel movies I love, like 'Primer' or '12 Monkeys,' 'Looper' is not about time travel. It's about this situation that time travel creates and the people dealing with that situation. So narratively, the big challenge was to have time travel get out of the way.