B Watson -

I guess I don't view taking a fourteen hour flight on an airplane the same way I take a job interview... or even a formal dinner... or even a casual dinner. I wouldn't kick off my shoes in a business meeting, but I've been known to do it at my desk and in my general office area.

On a 14 hour flight, my primary concern is comfort. When I fly transpac, I might show up to the airport dressed smartly (particularly if I'm hoping for a double-up or flying on CX/BA, etc.), but as soon as I am on the plane, it all changes... conditioner on the ends of my hair, no makeup and heavy moisturizer, and pjs or other cotton layers. I always shower as close to boarding time as possible when flying transpac (preferably at the lounge immediately predeparture). Shoes are not good for a fourteen hour flight as the feet swell. And my feet WILL stink if I wear the wool amenity kit socks for fourteen hours... then I feel sorry for my seatmate at landing when I take the socks off and put my shoes back on.
I would completely agree with it being gross to walk around the plane barefoot, to put my feet on the headrest or armrest of the person in front of me, or to go near the galleys. But I think that not allowing me to have my shoes off when I'm sitting at my seat is silly.