Having seen an A380 next to a 747, you get a sense of size that you don't with the 747. They are about the same dimensionally, when you're on the ground with Mark One Eyeballs. But the 747 is sleek. Its rear fuselage tapers so nicely, its wings abd tail surfaces have a lot of sweep, everything is sleek right down to the nacelle pylons. The A380 just seems to take up so much more room. The chord is thicker, the wing root is huge, the fuselage takes forever to start to taper. It's a chunky plane.