Well, shit.
I listen to music for possibly the majority of my waking life, and for that part of it over which I'm in control of the dials, I honestly can't come up with one scenario in which it isn't *necessary* to normalise the loudness, be it in order to be consistently audible over background noise, or to avoid pissing the neighbours off with the louder bits. (And I refuse to sit in my house wearing headphones, that's just wanky.) I guess some people are luckier :(