Assuming ro-bust-ability

I just realised that the word “robust” has the word “bust” within it. “Ro-bust” is essentially “un-bust-able”.

And having gone on that tangent, now we’re here, with a question:

What makes a house robust?

I’m not a structural engineer, or a builder, so I’m not sure what the technical answer is. But I’m interested in the assumptions that a structural engineer, or builder makes when they’re making the structure (in each of their own ways of ‘making’). No-one knows everything, and there isn’t the time to everything find out, so by necessity we must make some assumptions.

What are the assumptions that go into house design?