I think it applies personally as well as to families; you can be excited for an event, but you can worry about your clothes, your hair, your shoes, your smell, your smile, your voice, your style, etc. etc. It's very unlikely that you will be excited for your clothes or your shoes or your hair. So there's one kind of happiness but many kinds of anxiety. Similarly you can be content with your life, or discontent with your finances, home, relationships, etc. etc.

Same as a computer system has one way that works, but many things which can go wrong.

It's why entropy is a thing; there's only a few ways to build a stable structure, but zillions upon zillions of ways to build a crumbling pile of dust. Almost any change from wind/pressure/radiation will move it towards a less structured state.

It's related to why the Pyramids are so stable, they are shaped like the aftermath of a fallen building, a pile of stone can't easily collapse any further.

Indeed, it's why an exit code of 0 indicates a successful program execution, whilst anything else is an error code (which other programs can compared against known values, if appropriate).

You've given me hope that, one day, all the great Russian novelists will be translated into POSIX. :)