The fact that you're on the upper deck also means that you're flying business class, which contributes rather generously to the unearthly feeling. B-class on British Airways is something you could get used to. Not only is the BA service awesome, but instead of what I think of as "airline seats" to sit in, they've got these paired offset "pods" of motorized, fully-articulating things. Push one or another of the ten different seat control buttons and stuff happens: the seat transforms into a reclining loung chair, a work support, a fully flat bed, or a golf cart. Okay, I'm joking about the golf cart, but just barely. For each configuration, the seat back and seat pan shift, rise or lower themselves and tilt appropriately, the arm rests move into position, and as far as I can tell, haptic feedback devices adjust the thing until it determines that my posterior is being optimally pampered.
As I said, I could get used to this.
The one further thing about 64K is that you're at the window seat, facing backwards into the bulkhead. This combines with the interpod "privacy screen" (also motorized, more than begging for calls of "Shields up!" when you activate it) to give you a 360-degree isolation from the rest of the plane's inhabitants. It feels like you have your own little room there, with attentive staff, tasty food, hundreds of movies on demand, and three little round windows of the best view on earth.
I'm savoring the luxury, I really am - no idea when I'm going to get to fly business class again. So I'm trying my best not to get used to it.
[Postscript: during the flight I told Nina, the young Finnish flight attendant I'd been chatting with, that I'd heard tales of a crew bunk hidden in the vertical fin of 747s, and asked whether it was true. When she confirmed, I asked whether it might be possible for me to sneak a peak at it after landing - I'm curious about stuff like this. Absolutely, she told me, but since it was all the way in back and we were all the way in front, I'd have to wait until the plane had finished unloading until I could get back there to see it. And we'd have to be quick about it, since the cleaners couldn't come on until all passengers had deplaned.
So I hung back for a bit after landing while the plane emptied, and after a few minutes, Nina popped her head up the stairs and called up "All clear - let's go!"
As we scurried back through the last section of the plane, we passed one of her colleagues, who seemed surprised to see a passenger going away from the exits. Nina called over her shoulder as we passed: "It's okay, we're just doing a quick bunk visit." His eyes got reaaaally wide all of a sudden. I clarified: "To look at the bunks. To look." "Oh. uh, right." I couldn't tell if his expression was one of amusement, embarrassment or disappointment.]