I never considered the difference between a “mystery” and a “puzzle”, but Mónica Guzmán laid it out nicely in her book “I Never Thought of It That Way“. She said:
“People are mysteries, not puzzles. This means we can never be sure about them. But we can always be curious.”
This sparks a few thoughts in my head.
The first is the obvious one; you can never know everything about someone else. They might be your closest friend for 50 years, but there are always new things that can be discovered if you’re curious.
The second is that people tend to change as time goes on, and they should! If you hold all of the same opinions that you did 20 years ago, I have doubts as to how well-grounded those opinions really are. People change their minds, and your thoughts about them should change over time as well.
This could be your friend from high school that has grown more empathic because he’s had to care for his aging parents, or the politician you once admired that’s now in the middle of a financial scandal.
People change, and your curiosity should allow your thoughts about them to change too. They’re mysteries that should be continually explored, not puzzles to solve once and be done.