The only thing you didn't mention about the teapot is that it's also symmetrical on one axis but not the others! Unlike a cube, which is a cube from any angle with no true "top" or a microwave, which is plain and flat on all sides but one, or something like a beehive which is irregular and somewhat random, the teapot has the advantage of the base shape being the same at any angle (the lid and sides) but distinctive features in the spout and handle to orient it, and of course has a clear top and bottom (the lid and flat bottom). Furthermore, it's a recognizable shape and silhouette from any angle. An upside down teapot wouldn't make much sense physically, but is still recognizable as a teapot. It was a great piece in the history of 3d modeling and animation/game art!