The reason man does not experience his true cultural self is that until he experiences another self as valid he has little basis for validating his own self.
Whether the angels play only Bach praising God, I am not quite sure. I am sure, however, that en famille they play Mozart.
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.