If you have a good system you don't need loudness. The details are already there.
In fact, you know you have a good system when it's relaxing to listen to, doesn't sound loud, yet you're energizing the room. As I progressed up through the hifi chain, I found that this ease and relaxation was one of my favorite things about good hifi equipment. I can quite literally talk on the phone, chat with my wife, etc while listening to the hifi--and this at normal listening levels. With all the details. MMMMMMN
Bad hifi is just gets plain LOUD and fatigues my ears.