I'm actually happy close to 100% of the time even in the spirit of the question. It almost always puts a smile on my face to listen to my system. Without question, thoughts run through my mind occassionally during any given listening about what might be improved, but it's more intellectual than emotional, hence I remain happy but inquisitive. As stated in some of the other responses, my times of being less than happy are when the music I'm listening to isn't a particularly good recording. If I could get all the music I love to listen to in a recorded form that was equal to the best recordings I have, I'd never be unhappy. Which is not the same as saying I'd never upgrade again.
I have a combination audio / HT system - total cost is probably a bit over $30K retail, a bit under $20K of my $$ actually in it. -Kirk