I would never play things loud enough to cause clipping.
I just got carried away that one time. "Try it a little louder, try it a little louder" a little voice kept telling me.
For me the two main things I learned were one, well recorded dynamic music indeed can require gobs of power, as James stated and two that it didn't feel as if it painstakingly loud. The latter could be because the amp is so exceptional or the music is not compressed.
For the former I think it's not so easy to appreciate unless you have some clipping indicators or something (unless the amp falls apart in some obvious way).
But I am pretty sure I couldn't play it so loud on my previous amp which was rated at 320 Watts into 4 Ohms before I thought ok it's too loud. With the Bryston, yes it was loud, but not in a bad way. It was a very cool enjoyable grin inducing loud. Off course I turned it down just a bit so it stopped clipping and it was still great.
After this little lesson, I am very much in the more power the better camp especially for Maggies.
-- Sanjay