Also, shipping containers have a lot in common with soda cans: they have been engineered to have adequate physical characteristics within the very constrained parameters they are expected to operate under, and once they are outside that box, well, they're as fragile as soda cans.

For instance, if you try to stack your shipping containers any way but "directly square on top of each other, bordered by other shipping containers", you need to start over from scratch. All of those fancy stacks with one container crossing or bridging another come with lots of additional structural engineering to create the impression of whimsy. Or if you cut a big hole in one side of a shipping container to create a nice big picture window, whoops, you've destroyed the integrity of the container. Or you try to stack too much weight in the center of the top of the container, and no, that doesn't work either because the weight is supposed to be transmitted through the corners and sides.