A Barnum Statement is a phrase used by conmen (for example a psychic) to try and make people think they have some deep insight into their psychology or life.
They are also commonly used in horoscopes
Barnum Statements are statements which most people will agree with, regarding themselves, while not realizing that almost every other person will also agree with them regarding their own lives
examples are:
"you
have a good sense of humor, but not everyone sees it"
"you tend to think about things before taking action"
"You have had some major challenges
in your life"
"you recently had a disagreement with someone you care for"