There Are No Shortcuts To Knowledge

At breakup, people realise, "he never knew me at all". Why were they fooled before? It's because he was running functions like this:

define-action "care": (lookup-and-say: "conventional-way-to-care")

instead of like this:

define-action "care": (lookup-and-say: "what-partner-cares-about")

So as long as the couple is roughly conventional, things seem to work. They seem to have instant knowledge of each other. But they don't actually have knowledge of each other, and that is revealed when they get into more subtle parts of their personalities and find differences from both convention and each other.

The second function will respond to the partner changing. The first will not and is thus deeply impersonal.