First memory was also my first view of an A380 - soon after SQ started flying the A380 into Syd, sitting in Qantas Syd F lounge with a view to the N end of main runway. This enormous machine trundled very slowly past us, up to the end of the runway. As it began its takeoff roll I became aware that everyone around me, sitting in seats with good views out the floor to ceiling windows, had put down their newspapers, laptops etc, and either stood up or leaned forward to watch this aircraft move ever so slowly down the runway.
On it rolled, never seeming to accelerate, because it was just so big and out of proportion to anything around it! Like the ground was moving and the plane was standing still. It disappeared off to our right, past the Intl terminal, and the bloke adjacent said: "its too big, it'll never get off the ground.." I guess it did.
A more recent memory was doing a lap of both decks - escorted of course - after dinner on an overnight Sin/Syd flight. Walking back from our (new type suites) seat at the pointy end, back thru 2 blocks of J and multiple galleys/ sets of loos, to the rear stairs. Noisier, more flex and bumps back there. Step down to the back of economy at row 79, and walk forward a looong way before we get to PE, and eventually to the bottom of the front stairs leading back up to SQ's version of Nirvana ! There was only one thing wrong with that overnight flight - its too damn short. You can eat & drink but not sleep much, or you can squeeze maybe 5 hrs sleep. Could be worse - flight time to Mel is an hour shorter..